To add a new recurring post to your schedule, click on the schedule button in the left hand menu. Once there, you'll see the 'schedule new post' button above your calendar.
Click here and it will open a page where you can select the post type you want to add to your schedule. You can filter these at the top of the page by either pillar, or platform.
Once you've located the one you want, click 'add post' and this will open the next page where you can select the platforms you would like to post to from the dropdown, the frequency you would like weekly or monthly, and the time.
Once you've decided on these details, click the 'add to schedule' button (if it's greyed out there's something missing so have a quick check all boxes are complete).
After a few moments these should appear in your schedule.
Tip: The Schedule New Post feature is for adding recurring posts to your schedule. If you want to add a one-off post to your schedule, use the Create Post button in your left hand menu.