To add additional Instagram profiles you'll first need to ensure they are properly configured, which is explained in this help article. Once your other Instagram accounts are properly configured, you can add them with the below steps.
1. Log out of POPSMASH
Go to the profile page, click Switch Accounts then logout.
2. Log back into POPSMASH and select 'Edit Settings'
Log back into POPSMASH again and select Edit Settings on the Facebook permissions screen:
3. Select the additional accounts you want to use with Instagram
The process of selecting additional Instagram accounts is described in this article. If you don't see the Instagram accounts that you want to add they may not be configured correctly. See this article for help configuring your Instagram account so it may be used with POPSMASH.
4. Switch between your Instagram accounts on POPSMASH
Once your Instagram accounts are added you can easily switch between them in POPSMASH by going to to the profile page and clicking Switch Accounts.