Need help! New to working out!

[Nysse]

Hello, so i am really new to working out, i did just 3 hours earlier my third real workout. Yippie, so i have some questions to the more experienced people. So i have this app StrongLifts its been recomended for me and i follow it, and its ok, from my understanding it only alternates between 2 different workouts.
And i am wondering how long should i follow it, atleast 1month but after that, should i keep going with it for half 3months, 6months, more?
Also what should i do after that, i really want to build muscle so what should i do?
Last question, so what made me want to workout is seeing all the actors in tv, and movies and seeing that they are so ripped or muscular and i wanted to change from a skinny tall teen to a strong and muscular tall teen. And while searching around the internet i found this site: superherojacked.com
and i wonder is it stupid to later down the road, follow one of those workouts?

Well thanks for you help,m with my propably stupid questions!