I don’t have any experience with YNAB - I was a former Quicken user.
This was posted a few days ago and may help you get started with Tiller: Introducing the Tiller Video Tour Series
Also, if you use the Search feature in the upper right corner of this community, it will help you find other threads that you may find useful. There is an Envelope Budget tool in the Tiller Community add-ons, but I do not use it. Hopefully someone who does will see this and give you some more getting started assistance.