Yup. I personally like pine flakes. I use the flakes while there are chicks in the coop. When they get bigger, I usually use fine shavings. I also use shavings in the nest boxes. I have used straw, but the girls don't really care one way or the other. I do use straw in a nest box though when I have a broody hen. I find it safer for the chicks she hatches.
Measure the size of space you need a pan to fit, then go to a Gordon Food Service store, or something of the like, and get a tray pan to fit. I personally just use the lids from off of those larger sterite tote/storage boxes.
Also, you could just put tile/linoleum on the floor of the coop, makes for real easy cleaning.
AND, you may want to consider placing that coop you got from
TSC in as protected area as you can. They may look nice and all, but the wood is thin, you will need to treat it each year. I have one from them, the dog house, its made of same material. I put mine in the garage in the winter... BUT we have some very screwy winters here.
Welcome to BYC.