First off...
Your Instagram account must be a PROFESSIONAL INSTAGRAM ACCOUNT. (If you don't have one or need to make one, learn how to do that here.) Once that is taken care of, you can follow the instructions below.
1 . Navigate to the Social Networks Page and click "Link New Instagram Business Account"
2. Authenticate through Facebook > Click "Connect with Facebook"
Because Instagram Business accounts are linked to a professional Facebook page, users must login with their Facebook account. Facebook users must have a role of Admin, Editor, or Moderator on the Facebook Page that the Professional Instagram Account is connected to in order to authenticate properly.
** Please Note - You cannot login in directly with the Instagram account - It must be done through Facebook.
3. Grant Access to Photoboxx through Facebook > Click OK
The facebook website should open up on a new page. (if not, please ensure your browser is not blocking popups) You may need to login first in order to grant access as well.
4. Choose the Instagram Business Account(s) you'd like to link to Photoboxx > Click OK
This Instagram Business account will allow Photoboxx to be able to gather posts where you have been @mentioned and search public content (#hashtags) on Instagram on your behalf.
** Note: If your Instagram Business Account is not showing up at this step, please follow the steps in this troubleshooting article to resolve this issue. This is still a new process/workflow to Facebook/Instagram and they still have some known issues for some accounts and have provided workarounds.
All done!
Once you've linked up your Instagram Business Account, you can begin using the @Mention Feed and Hashtag for your events!