If you can use Win 7 Linux is a breeze. It is almost exactly the same in how it operates, mouse click menus and all. So here is how it works. You have to first download a Linux distro and make a USB stick with the Linux on it, you will want to use a 3rd party program called “Rufus”. Not only will it be a “test drive” stick you can run Linux from directly, but it is also your install and repair stick if you have to repair your Linux for some reason.
To dual boot is called “along side” in the Linux world. To install as along side you boot up into the stick and choose “install Linux”. Go step by step through the install set up, language, keyboard, location, PC name, Etc. (you do not have to use your real name, it doesn’t care, so If you want to be discrete use an anonymous). Linux is yours, so you will not registering and you are not setting up any accounts with Linux.
During install it will see your Windows and then ask you if you want to “install alongside” or erase the drive and install only Linux. Choose “Install along side” if you want dual boot. It will install the Linux next to your windows slick as snot.
When done the next time you power up it will give you a menu for 30 seconds that will let you choose between Linux or Windows to boot that session. Default Linux will be the primary OS that it automatically boots into if you just ignore the boot menu at power up. Later there is a simple one line edit in Linux you can make to have it boot into windows as default primary if you prefer.
As for how it works with apps you will actually have two completely different systems with all their own installed apps in separate drive partitions. Basically two different computers on the same machine. They will have their own browser, apps, drivers, etc unique to themselves. The systems will be isolated from each other completely with their own apps except for the file manager.
The Linux file manager will indeed let you go and manipulate your windows files when booted in Linux. So after you install Linux you can go and copy or move all your pics and such from windows over to the matching Linux folders. Just drag and drop them from windows to the Linux folders just like windows 7 does. Pictures, videos, documents, music, downloads, etc. can all be moved over to the matching folders so no need to pull all those files off to external USB and then have to put them back into the Linux folders from USB.
As for using Linux just think using WIN7. Please consider Linux Mint Cinnamon. It is the very very best for first time users. Good luck and hope to hear you are up and running Linux soon! You will never look back once you lose that MS ball and chain!
P.S. If you get the Mint Cinnamon it comes packaged with a whole suite of apps already installed default. Just about everything you will ever need comes with it. And the whole thing is still only 2 gigs compared to 18 gigs for window 10.