First, search the help docs and this forum. Maybe your question has been answered! The debugging steps can help, too. Still stuck? Delete this line and proceed.
If any line is invalid, the entire yaml is invalid, so to properly try it out you need to test one version at a time.
In LTR the following is valid:
---
Tags: testTag
---
When you switch to reading view it should display this as “#testTag”. So your first goal would be to get that output in your RTL environment. After that add line for line, keeping the same format (or alternate it a little when doing lists).