Like the previous posts, if you don'tmix it thoroughly, it just stay sticky. I roll it out, fold it over, roll it out fold it over, etc about 10 times. Squish it, knead it, pinch it, twist it, what ever it takes to make sure it's good and mixed. Make sure the are you are applying it to is clean, then just press it in. Shape it how you want it using your favorite tools dipped in water and let it dry. Just remember, when that stuff dries, it's hard as rock and when you sand it down, you will remove the plastic/resin before you remove the putty! :-)
Jesse