Patch

So I'm 19 and finally decided to get the patch since i have a hard time taking pills. I'm super confused about when to start it, since my period ended last friday (December 16) and i got my prescription last thursday. do I start taking it on the first day of my next cycle or can I start right away? I just don't want to mess anything up. I got it from my health clinic at school, but they are closed for the next two weeks so I can't contact my doctor there. 
Also, has anyone have any bad side effects from the patch? I've only ever used condoms, no hormonal contraceptives, so I'm scared about that too. 
thanks!