rewrite it in the correct order

[kachy Gozie]

et puis, cet apres-midi, je dois preparer mon sac parce que demain c'est la rentree

[Frank]

Looks like it's in a correct order.

"cet après-midi" could be placed after "mon sac", but the way you wrote it is correct as well.

"et puis" is a bit redundant, though.