How to Link Instagram to Facebook Business Page
Using Facebook's Page interface
1. On Facebook, navigate to the business' Facebook page.
2. Click Settings.
3. Click Instagram in the sidebar.
4. Click Log in.
5. Enter your Instagram qualifications. Click Log In.
Making use of Facebook's Business Manager
1. On Facebook's Business Manager, click Service Settings.
2. Click Instagram in the sidebar.
3. Click Add.
4. Go into the business' Instagram credentials. Click Next.
Optional: Connect any kind of relevant Advertisement accounts. If you do not wish to add one, click Avoid.
5. Click Done.