Step #1 - Go to your account's profile page

In another window or tab login to the Storm website.  In the upper right corner there should be a button labeled MY ACCOUNT.  Click it to go to your account's profile page.

Step #2 - Click the edit participant information icon

In the middle of your account profile page should be a section title Participants.  Click the edit participant information icon (looks like paper and pencil)

Step #3 - Scroll down

Once you are on the participant information page, scroll down until you see the drop down lists for the uniform sizes.

Step #4 - Select the desired uniform sizes

Select the desired uniform sizes from the drop down list.

Step #5 - Click Update

Once you have selected the desired sizes, scroll down to the bottom of the page and click Update to save your changes.  The changes will not be saved until you click this button.