To connect your Instagram accounts for direct posting with Postcron click on the + sign button at the top right side of the screen and click on Instagram. Then, select Business.
Keep in mind that direct posting only works for the Feed and there are two requirements: you need an Instagram Business account, and it needs to be connected to a Facebook Page. You can also connect other types of accounts to post with notification reminders. Learn how here.
If you're already logged into Facebook, you'll see a list of Instagram accounts connected to your Profile. While if you aren't, you will be prompted to log in. Make sure you log into the profile that has some sort of admin role to the Facebook Page that's connected to the Instagram account.
Now, in order to connect one of the listed Instagram accounts, just click on the + sign button right next to it. If the account you're looking to connect to isn't listed, click here.
The social accounts you connect to Postcron will be displayed on the upper part of the screen. If they're Business accounts, you will see the Instagram logo alongside a flag icon to help you differentiate them.
Postcron will prompt you to accept some publishing permissions to post on your behalf. Make sure you accept all of them to avoid future publishing issues.