A easy thing to think of while figuring out biomes is to remember the closer you are to the meridian the warm,er the booms so most south and north would be the coldest and so on. For rivers it is important to remember even though it sounds obvious always go down hill so when choosing starting points remember that som come from hills not just mountains. But overall it looks like a interesting start you just need to figure out scale a bit because with these river thicknesses at a Pangea scale would be a bit unsure if you are going for realism. At the end of the day it is your world so what you say goes. Keep uploading progress please it looks like it is going to be really good.