"How does one become a Free Mason?"
All you have to do is tell a Mason that you want to join. A Mason will neve ask you if you want to join.
There is a petition, werein you are asked certain questions, such as "Do you seriously declare, upon your honor, that you firmly nelieve in the existence of God, the immortality of the soul, and the Divine authenticity of the Holy Bible?"
You also have to have all your limbs --- but this bit can be waived. (Left over from when it was a trade union.)
You'll need some referrals -- which can be provided for you.
And there is an investigation period, which is basically meeting you & your spouse.
But, to answer your question, GO ASK A MASON and EXPRESSLY ask to JOIN.
Does the fact that my grandfather is a high level Mason from the Dominican Republic help?