Making plum jelly, need help.?

Ok I've got 2 gallon bags of plums. Due to illness I couldn't make the jelly while they were fresh.So I froze them. My question is do I have to let them defrost completely before attempting to make the jelly or not. Any recipes you may have would be helpful and much appreciated.I don't know what the type of plum they are just know that they are larger than golf and are yellow and some are pink.