@tpr "A beginner should learn the game, not opening theory."
Very true, but it exactly disagrees with 1.g4 .
Even though in some deeper sense it might fight for the center and do all that stuff, at least to a beginner it looks like you should move your flank pawns for no reason and not devellop pieces.
If you play 1.Nf3 you don't need to know any theory either. Just play normal moves and white is fine.
" If white can play 1 g3, then white surely can play 1 g4, which is more active"
So how comes then that g3 is objectively better than g4? Simple, g4 creates a weakness. With g3 you can just go Nf3 Bg2 0-0 with a very healthy position, with g4 you can't so easily.
It sure is a good idea to tell a beginner to not concentrate on openings but instead on the game. But g4 for that is just stupid if you don't already know enough about chess to possibly understand the nuances of why one would play it.
So
@Justice_Roberts , just play "normal" moves, i.e. moves that fight for the central squares and devellop pieces. Then you automatically will get to move like Nf3 (devellops a piece, fights for d4, e5), e4 (fights for central squares, frees the bishop and the queen), d4 (same) etc.
You don't need to know much theory in those openings because if you play unusual moves you opponent won't know the theory anymore either.