Type Koverall in the search box and you'll have DAYS of reading in front of you.

Koverall is a heat shinkable Dacron fabric. There are a number of different ways to apply it to your airframe. Each method has its pros and cons. You can use Sig Sticks It which is a heat activated glue applied to the airfame with a brush. Then cut the Koverall to size and iron it down.
You can also use Nitrate and thinner to apply the fabric prior to shrinking it with heat.
I'm sure there are other ways to apply it.

Once it's applied, you need to paint with your choice of paint.

There are as many ways to use Koverall, so read up and pick a method that make sense to you.

Good luck!