When to start NuvaRing?

I just started NuvaRing about 3 weeks ago.(switching from Ortho Tri cyclen Lo, which I was off of for about a month) I inserted it the last day of my period. Was I supposed to do that? or wait to insert it on the 1st day of period? I'm kinda confused becaused I've heard from different people that you're supposed to insert it the 1st day of your period and I've heard from other people you insert it the last day of your period. Please help! I'm supposed to insert a new one in on July 9th. (July 2nd-9th I should have my period) And since I've been using it, I havent had any symptoms. Normal or no? Thanks for your answers in advance!