Tutorial
Intro Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Step 10 Step 11
Step 9:   When you've fashioned the profile to your liking, click the "Assign Profile To Experiment(s)" button at the bottom of the page.

You'll arrive at a page entitled "Assigning Profiles" where you'll need to find your new profile and your new experiment instance from the listings available.

For detailed directions on using this utility (in the pop-up help window)