After scheduling your posts, you can move them to Draft mode in case you need someone else to approve them or if you don't want it to be posted just yet. They will still show up in your Future Posts, but won't be posted unless they are approved.
Here's how you save them as draft posts:
On the side menu, go to the Scheduled Posts section. On the top of the page, select the social account the post is scheduled to and select the Future Posts tab. Then, locate the post and click on the checkmark button. You'll notice that your post will get grayed out. If you're on the Compact View, you'll have to click on the 3 dots menu button first.
When your post is on Draft mode, you'll notice that it will still show a scheduled date, but don't worry Postcron will automatically postpone it until you approve the post.
To approve posts, click on the same button again (forbidden icon). Your post will be displayed in colors and will be posted on its scheduled date.