You can schedule a new post to your personal Instagram account by clicking the big yellow 'New post' button in the top right hand corner or by clicking the plus button on the day that you'd like to schedule for, directly on the calendar.
Due to Instagram's own limitations, Simplified’s content calendar can't automatically publish your personal Instagram posts. You will have the following options:
Publishing now:
Publish your posts by creating them, then clicking on the 'Publish Now' button.
or
Scheduling posts:
If you want to plan your posts:
1 - when you have finished editing your post, click on the 'Schedule' button
2 - choose a day and time when you need your post to be published
3 - you will receive an email reminding you it's time to publish your post.
4 - open the Content Calendar, click on your post, then click on the dropdown arrow on the right side of the 'Schedule' button, and choose 'Publish Now'. Or just click the ... button on the top right corner of the post on calendar view, select the Publish Now option, then click 'Yes'
For Instagram Personal accounts, due to Meta's API restrictions, auto publishing isn't supported. You will receive a notification (either via email or via the mobile app) reminding you it's time to publish you posts. Copy the assets, paste into Instagram and manually publish your posts, For more details, follow the steps in this article.