I need a little help knowing when to start the first G chord in the song. never played along directly with anything

https://www.youtube.com/watch?v=wlpFcSSCO3g

I was wondering how long should expect it to take to memorize all of the scales, modes. etc?

Just uploaded 7.1 Chords II which gets into 7th, suspended, add9, slash chords, and inversions. Also just uploaded 8.1 which walks you through the 7 positions of the G major scale. I recorded a bunch of lessons this weekend so get ready!