I'll try to offer you suggestions, but it's going to be difficult doing it via the internet. You would be better served finding someone local that could help you hands-on.
Once you have compiled a list of the repeaters you want to put into your radio, you can either program them by hand (a complicated process for someone new) or you can use programming software. While Yaesu does produce software for this radio, the programming software from RT Systems is head and shoulders above anything else out there. (Link below.)
There are two ways to program the FTM-100 from software. You can either use the SCU-20 cable that came with the radio or you can write the programming to a MicroSD card, insert it into the radio and read the files from it. I find using the MicroSD card easier because it means I don't have to carry a computer out to my truck when I want to make changes.
https://www.rtsystemsinc.com/FTM-100-programming-software-and-USB-cable-s/2409.htm
There are two ways to go with RT Systems. You can buy the software and MicroSD card w/reader or just the software alone. Your choice.
The software is very easy to use, especially if you've had any experience with Microsoft Excel. Another nice feature of the RT Systems software is you can copy and pate information from one radio programmer to another. I have several dual band radios and I use the same layout for all of them. A couple of things to remember is that when using cables to program other radios, their software only works with their cables and it only runs on a Windows platform.
I've included a lot of information for you to digest. Good luck.