You are very right to think about what to do with the cockerels. A little over half the eggs that hach will be cockerels on average. You will either have to rehome or cull them.
There is some good advice on how to cull cockerels. If you type
culling cockerels into the search box in the top right-hand corner you should find plenty of information.
Also it is not easy to tell which are cockerels and which hens until they start crowing or laying.
I have never used in incubator as I am using a broody hen. I'm sure someone with experience in incubators will be along to advise you.
In the meatime good luck
PS don't forget pictures of the chicks when they hatch