Need help building incubator please thank you

Need to know how to build one ty much

An incubator for what ? ?

Chicken eggs . . .

If this is for your mushrooms... an incubator isn't necessary

How do you keep warm so it grows at good rate?

You keep the room warm. No need for eighty degree temperatures. They will grow at Seventy five just fine.

Hey in my pf tek cakes you can see white vermiculite you can see brown vermiculite are they the spores germinate?

Vermiculite is brown. Unless you put perlite in your cakes,If there are white areas, it's probably mycelium beginning to grow