I've created an item that is meant to apply 1 level of exhaustion.  I cant seem to make it effect the character sheet. 

Ive selected "Condition - condition name = exhaustion" then tried every option I can find in the interface, but when I equip the item exhaustion is not showing.  

Whats the trick here? or is this a bug??

It is not currently possible to create an item that will automatically apply any condition to the character. 

Well, that solves that problem.

Is there an FAQ or single location that itemises what you can or cannot do? It will stop me wasting many hours applying properties and testing them.

This is the most comprehensive FAQ that exists: (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq). It doesn’t have all the answers, but it has a lot.

Thank you