If you have just started your first period, the pain from cramps may become excruciating. It may take some getting used to as the pain will make you feel very irritable for quite some time. 

Things that may help:

You can take over-the-counter pain medication (please consult your medical practitioner) These may help you get immediate temporary relief.
Use a heating pad, heating wrap, or other heat packs to apply warmth to your stomach or lower back.
Take a long, hot bath. Nothing feels better than soaking all your pain away.
A great home remedy to get rid of cramps would be to drink a warm cup of black coffee.