It depends on how you have setup your accounts as to how you switch between your Affiliate and Advertiser accounts.
See below for more information on how to login to either the Affiliate side or the Advertiser side depending on how you created the accounts:
Accounts registered to different Email Addresses
If you have both an Affiliate and Advertiser account registered on WOW Trk but with different email addresses, then depending on the email registered to the account will depend on which account you login to.
Accounts registered to the same Email Addresses, but have different Passwords
If both your Affiliate and Advertiser accounts are registered under the same email address then it depends on your password. If you have 2 different passwords set then depending on the password you enter will depend on which account you login to.
Accounts register to the same Email addresses and same Passwords
If both accounts have the exact same email and the exact same password then when you login you will be shown a message to let you select if you would like to login with your Affiliate account or Advertiser account, the message will look like the below: