First time formula user please help

In a mother of an almost 7 month old and I have been exclusively breastfeeding but now that I'm trying to go back to work and pump a good freezer storage amount I need to supplement him with formula every now and than. The formula I use is Similac (sensitive for the tummy kind) and it would just turn out so thick and foamy! I would like to know if anyone warms up there formula after mixing? And how? Please let me know thanks y'all:)