If you want to show posts from someone else’s Instagram account, you will either need access to log into their account or they will need to provide you with their account ID and Access Token. If you are logged into their account, you can go to WordPress Dashboard > Instagram Feed > Settings, click Add Source, then click the blue login button to create the connection.
Alternatively, they can send you their account ID and Access Token, and you can then connect their account in the plugin manually. They can retrieve their account ID and Access token with our tool here: https://smashballoon.com/instagram-feed/token. Once you have the ID and Access Token, you can go to WordPress Dashboard > Instagram Feed > Settings, click the Add Source button, then click the Add Account Manually button and enter this information here.
If you need more information on how to generate an Access Token, please follow this guide: How to create an Access Token and User ID to Manually connect an Instagram Account.
