...making the top bunk bed???

I just spent what felt like forever trying to get the fitted mattress protector and fitted sheet on!! Our bunk has a wooden rail right around it, which makes pushing the sheet down the side quite hard, and i'm lifting the mattress from underneath to try and get it under.

I only have access to 2 sides of the bed too.

What I'm doing at the moment...

fit it over 3 corners as best I can while standing on the floor... then I climp up and somehow manage to lift up that final corner, while I'm kneeling on the mattress, to get it over. Then the top sheet just kinda gets scrunched down the sides, but isn't really tucked in properly. It's really irritating me LOL.

Is there a knack to this?? How do you do it?