I don't know why, but Facebook love to keep changing things and confusing everyone! Due to recent changes, now, to schedule posts you have to go a different way.
Old news
Previously, you could create a post in Facebook and choose from the drop down menu to "Publish now" or "Schedule for later" or "Save as draft".
Ah, the happy days of old! Skipping down the street eating ice-cream....
New world order
Now, this "Schedule for later" function seems to have deserted us, like a jilted lover or friend.
Now, you need to either:
1. save as draft, then go back in to drafts and schedule for later, or
2. go to publishing tools first, then create and schedule your posts
Actually, it's really not that hard once you get used to it, and I hope this guide has helped you....
Happy scheduling!