i used this pattern by ashlea from hearthookhome:
https://hearthookhome.com/wrap-swimsuit-cover-up-crochet-...

i adjusted the size to be made for my 7yo daughter. the width was 18”. the final length (including the 2 rows to make the arm holes on each side) was 40”.
1 skein polo stripe made the entire rectangle piece, but i didn’t have enough for the arm hole rows/straps/edging, so i used some yarn that i had which matched the green in the polo stripe (red heart with love in fiji stripes).

i did not fasten off to make the straps or the border edging. after making the two rows to create the arm holes, i continued with the yarn attached, made 15 fsc and attached to the corner to make the arm strap. i then continued to make my 2sc in each 2ch space across the top to the next edge to do the other arm hole/strap. i had to skip stitch in one small area to avoid having to cut the yarn.