Switch to Professional Instagram Account
First of all, you should create an Instagram account. After that, in order to convert this account into a Business Instagram account, you need to go through the next steps:
1) Go to the Settings section and click the Account button.
2) Click Switch to Professional Account and choose Continue button.
3) Select a Category and click the Done button, after that select Business and click the Next button.
4) Review your contacts and click the Next button. The most important part is to connect the Instagram page to your Facebook page, so click the Login to Facebook button and sing in to your FB account.
5) Select the page your want to connect and click the Next button. Next time you want to check if Facebook page is already connected just go to the Settings > Account > Connected Facebook Page (Linked Accounts).
Connect your Instagram page to Post Studio
After you've converted your Instagram personal page to the business page and connected Facebook page, you need to connect your Instagram page to Post Studio:
1) Click on the 'Change Pages' button in the Facebook / Instagram section and then click the 'Connect Pages' button.
2) Click the 'Edit Settings' button, select the Instagram pages you want to connect and click on the 'Next' button.
3) Select the Facebook pages need to be connected.
🚨It is important to connect the Facebook page to which the Instagram page is connected, otherwise, the Instagram page won't be connected in the end.
4) Check that 'Yes' is selected on all items for correct system operation and click on the 'Done' button.
5) Check all pages and click the 'Select' button.