The LSPDFR mod is just a simple installer, open the file and point to your game install and it will do everything, however there are several extras available such as stop the ped, computer+, interactions+ ect. These usually just copy directly into the game install folder so no real modding skills are required. To be fair most mods should come with a readme file. Read that and you should not have a problem.
With this being said, before installing ANY mods to GTA V you should make a 2nd copy of the game if you intend to play online as you WILL get banned from GTAO if you go online with mods.
There are plenty of helpful people around so if you get stuck feel free to ask.