Is there something I can do to keep sustain on? I play with simple qwerty keys and I dont know how to enable the sustain pedal- if there even is one? If not then please add one :]

Hello!

You should be able to hold spacebar while playing to enable sustain! There is not currently a toggle for it, you'll have to hold spaecbar the whole time, but that's something I can look into adding in the next update!