This would be a lot easier to answer if you had some knowledge of chemistry.
Chemicals like carbon, hydrogen, oxygen, etc., react spontaneously to form molecules because it is their nature to do so, just like it is the nature of magnets to seek physical contact when placed a short distance from each other. Each carbon atom can form covalent bonds with up to four other atoms. Each nitrogen atom can form up to three bonds with other atoms. Each oxygen can form up to two bonds, and hydrogen only forms one bond. As long as energy is present in the system (in other words, the mixture is warm enough), those bonds will form--it is unavoidable. And since they form randomly, a variety of organic molecules results.
As for how the oxygen and carbon came to be, they were produced from the fusion/other nuclear processes of hydrogen atoms inside stars. As to where the hydrogen came from--well, I believe that is a topic of discussion among physicists, who will tell you that everything came to be in the big bang, but don't really have details (or, at least, an explanation of how all this matter came into existence from nothing during the big bang). I can't answer that, and I don't spend time worrying about it.
Next, the early earth did NOT contain free O2 and early organisms did not respire the way all eukaryotes and many prokaryotes do now. All of the O2 currently in the atmosphere is there because of biological activity.
So many questions. Are you really meaning to say that DNA (deoxyribonucleic acid) consists of 4 letters.. A,T,C, and G. Or did you mean those letters represent nucleotides. And if so, please tell us how chemical nucleotides convey this 'tangible information'. Would it be more accurate to express this 'tangible information' as the physical expression of information contained in the genetic code. If you agree with that expression, then how did chemicals 'tell' messenger RNA to move to ribosomes and produce a protein. Information -> Nucleic acid -> mRNA ->ribosome ->expression of information. Now, what is the physical makeup of information.
Of course, the letters represent nucleotides. Within the scope of this discussion, and, indeed, within the scope of many scientific discussions, the pertinent information about those nucleotides is conveyed by referring to them as letters.
Now, when I speak of those chemical molecules carrying tangible information, I am being absolutely literal. Every atom, every molecule formed from atoms, has a unique shape. Carbon, for instance, is a tetrahedron. Molecules have more complex shapes than atoms. When a messenger RNA molecule is threaded through a ribosome, a single word (or "codon" in scientific speech) is placed in a specific position on the ribosome. A transfer RNA with an amino acid attached sees that word. If its word ("anticodon") is the exact opposite of the word at that position on the message on the ribosome, it fits that word just like a key fits a lock. The entire process is very physical. Here is a video that shows the process of protein synthesis on a ribosome. Although it's only representing the nucleotides as letters, the actual nucleotides do have specific shapes that only attach to other nucleotides with complementary shapes. A can only attach to U, and C only to G.
Now that you have the obligatory insult laid at my feet....you may presume that I have some knowledge in the area of chemistry. But you may also assume I am ignorant in many areas...of that I plead guilty.
We will bypass the fundamentals on covalent bonds, ionic bonds, electrovalent bonding, and nucleosynthesis. Presume I have a working knowledge there.
Molecular oxygen and carbon you account for via nucleosysthesis. Then you hand off the ball to the physists as to the origin of Hydrogen, helium (not mentioned) and subatomic particles which must have existed very early on in that event which you referenced as the Big bang. The fundamental question which I originally asked was,....As we know, and you affirm an origin to the universe (hydrogen, carbon, oxygen, etc), and given that science does not deny, yes, it affirms that the universe came to be from nothing, (the eternity of the universe has thoroughly been scientifically dismissed-(see Borde, Guth, Vilkin) please account for the Cause of the big bang. Everything which comes to be has a cause....the universe came to be....therefore the universe had a Cause. (Please, before you go into the Heisenberg Uncertainty Principle, Copenhagen Model, the above referenced authority has disposed of it). This was my question to you.
Next, the early earth did NOT contain free O2 and early organisms did not respire the way all eukaryotes and many prokaryotes do now. All of the O2 currently in the atmosphere is there because of biological activity.
Therefore you say these early organisms were anaerobes. I will assume you will agree with this. Do anaerobes give off elemental O2 as a byproduct of their physiological process (For now I will not ask you where and how the enzyme process survived an atmosphere in which was highly reduced.) So how did they respire? BUT, before you answer that question how did this 'primitive life' come to be?
Now, when I speak of those chemical molecules carrying tangible information, I am being absolutely literal.
Tanglible...ok. I understand that word. Now INFORMATION....we need to look at that word. That is an interesting word. Is it a 'piece of knowledge', as Webster indicates or, as Websters also indicates, is it 'the attribute inherent in and communicated by alternative sequences or arrangements of something that produce specific effects'? By this last definition it indicates a string of characters, specifically which indicate a particular outcome or performs a communication function. So DNA contains particular sequences to a specific effect. What humans recognize as 'information' always originates from mind or consciousness when applied to our technology. The information in the books of Tolstoy, Dostoyevsky, and Shakespeare originated in the minds of those men. In nature the only place we find 'information' is in our biology, indeed in the cells of every living organism. So my question is...."How did this information arise?" Who or what wrote this book of life? It seeems to me that DNA is the medium which holds the information, not the the information itself. DNA is like a CD. It is not the music recorded by the Os and 1s sequenced in the CD. Who wrote the song? What wrote the song? As you know you can go into the lab and extract the molecule DNA (or pieces of it) put it in any medium which you desire, and you will not produce an organism. There is all the information you need to produce an organism, but there is no execution of production.
Thank you for the link to the video.