Hello! I was playing some online games on a different site and I played 2 games in a row that the other player allowed me alot of space. I won both games but I dont know how more space turns into pressure and that pressure turns into mistakes. If you could help me out that would be great!

That's a good question! Pressure, for me, in chess, usually is a bluff, since I rarely calculate past a few moves or so. I have had an advantage in a position, where my opponent puts pressure on me by keeping the position somewhat hostile while I try to simplify. When I break, is it because they really just play better than I, or am I succumbing to the pressure I'm creating in myself? Maybe that's just psychological pressure, and not the kind of pressure you're talking about?

It looks like you did a good job in the second game.
Move 8 - stopped Black from castling by planting a piece on d6
Move 16 - a little shaky forcing the knight to e6 where it wants to go
Move 19 - I think the bishop is a target on d5, I'd think about backing up to b3 and keep pressure on f7
Move 25 - Rh2 crashes the party
Move 27 - Maybe a little premature I'd get my king off the file and play this then I can load up with the rooks on the c file
Move 30 - excellent anticipastion! and finally Black cracks
Move 37 - Nd6 trades off a piece with an easy win
Move 38 - Keep Black tied to defending f7
Move 42 - Rxf7 seems better

I think when you have a super bind like the knight on d6, just keep improving the position of your pieces by building to the pawn break or line opening you decide on. In this case you already had the h file open, but failed to crash through. You could also shuffle your rooks back and forth and let your opponent suffer until he decides to lash out by sacrificing the exchange or a pawn for activity.

If you don't have that nice of a bind, just decide on a pawn break and build up to it while your opponent is dealing with your pressure.

Hope this helps