For some reason I can never remember how to do this, therefore I have decided to make a post on this. In order to see and edit your scheduled tweets click the schedule button as seen below:
Then click on the scheduled tweets button (this is what I always miss!):
You will then see all your tweets, you can click on any of them to edit them and then reschedule them.
I hope you found this post helpful! Let me know in the comments down below if there is a less cumbersome way to see your scheduled tweets, I have sadly not found it :)