Grippy Shoes - probably a stupid question..but..

Hey guys, I'm beginning the intermediate class tomorrow (so excited/nervous) and we've been told to bring our grippy shoes/boots with us. Thing is, I got a pair of boots before (they looked sooo cool!) but they were SO slippy, I couldn't even climb in them, whatever the hell was up with the material. I have no clue about shoes and grippy-ness so what material should I be looking for? Is it leather or what? 😲 😕 Sorry for the bizarre question 😜 Fairy xx