To add your location to your Instagram post, first choose or take your picture or video and continue to the message section. If you do not see the location you want to tag below "Add Location", click on "Add Location" and select your location from the list. You can also type in the location name to find it.
Once you select the location, it should show below your post. You can also select to post this to Facebook in order to check-in. The Facebook check-in will count as an additional donation.
When you view your Instagram post, you should see the location included below your Instagram name.
To ensure your post becomes a donation, make sure your Instagram account is made public. For more information on making your account public, go here.