Making my first world

Howdy so i did a little research the past few days because i wanted to make a somewhat scientifically accurate world map but i am still struggling with how to decide the shape of the land masses...

i have created a map for the plate tectonics (last image) and decided on the continental plates (o = Oceanic, L = Continental), now to get a better idea on how to flesh out the continents and islands i am rewatching a video by worldbuilding corner, however i am confused on how he got the final shapes for his land. some of it makes sense to me but a lot of it i cant figure out.. and what's with the two massive spots of land at the top and bottom where he marked oceanic plates??

if anyone can help me figure out how to decide the shapes of my continents that would be appreciated..