Collard greens taste much better after the first frost.
The are not as strong tasting after being frosted on. If you plan to cook them now I think I would blanch them then freeze before cooking.
I cook collards a lot in cooler weather. Everyone likes to eat them along with cornbread.
First thing to do is wash/rinse throughly, cut onto mediun strips (similar to how you would prepare lettuce for salad)
Place in a large pot, collards will shrink a lot.
Add enough water to cover about 1/2 of collards.
Add Salt. I also add about 2 to 3 tablespoons of honey or syrup. Cane Patch syrup is best, a Southern thing.
My daughter always puts a whole pecan in pot while cooking. Helps the smell.
I do not add any fat meat or any oil.
Cook until tender. My family likes them tender but not mushy.
Adding the syrup is the old southern method.
Sorry this is so long, but good cooking takes time.