any tips for creating lakes and rivers for your world ?

i’ve just got done drawing out my map and now i need to draw the geography for it. i’ve just finished my mountains but the thing i’m struggling with are the body of waters.

for context, my word becomes a super continent since it’s set into the thousands of years into the future. i’ve done some research and rivers are formed by elevation from higher to lower ground, especially with mountains. i’m struggling more with the lakes. i’ve tried to draw it out but it just seems really, really wrong.

thanks :) !