If the event you registered for is set up for fundraising there will be a donate tab on the race page.
There are 2 ways to set up your fundraising dashboard.
From the race page select donate - raise funds. Set your fundraising Goal, Donation End Date ( default date is the date of the race) and personal message. Select Set up fundraising account.
If you are logged onto your profile go to the fundraising tab and select visit my fundraising dashboard.
Select set up fundraising for my event. Select the charity you want to raise funds for. Your fundraising page is generated where you enter your fundraising goal, Donation end date and send out emails to friends and family soliciting for funds.