could anyone help
I'am new and i want to enjoy downloading mods and i want to know what will change in the game
another question:could i have lika a family for franklin and make them follow me and control their actions
i want to know what will change in the game
That's a bit of an open question to be honest. What will change in game, is whatever the mod you install changes. If you install a vehicle mod, vehicles will change. If you install a Ped mod, peds will change. If you install a script mod, anything and everything could change.
As for your last question, you can't have a family for Franklin, but you can find mods that let you create bodyguards that will follow you around.