how do i know im getting them right

Ive only had my KM for 2 days and used it each day. Problem is im not sure if im isolating the right muscles. When i use it (1 spring on post 4) i can close it but i do feel like i get a slight tightening of my buttock muscles, will this harm? Also im scared to think that its in the "wrong place" could it not go infront of a prolapsed uterus and push it towards the back of the vaginal canal? As you can guess from this im worried and scared of getting it wrong. Unfortunately I ordered my KM from another site (how dumb) and recieved nothing but the unit itself and a leaftlet. Why didnt i find this site first!!!