We use the Instagram Feed plugin by Smash Balloon to integrate an Instagram feed.
It is free but also has a Pro version available.
To integrate you need to be logged in to the clients Instagram feed for the feed to be accessable on the site backend.
Instagram login > Add & activate Instagram Feed plugin > Configure settings
I tend to set the measurements to 100% height and width.
Otherwise there will be a scrolling menu added to the frame.
And that’s it!
Once you exit the site remember to log out of Instagram and back in under your own account!