I gotta be blunt and straight with you. It sounds like you are building your yurt off grid, and uninspected, or the details of the propane heater would be worked out before the plan was stamped by the building dept.
If that's the case, realize the risk. If there is no
professional involved on the heater install sorting out what is safe, you are absolutely taking the safety of occupants and your investment into your own hands. No to mention the public if you cause a fire that spreads elsewhere.
Fire safety is a REAL big responsibility here in the U.S.. This isn't Tibet, Mongolia, or Nepal. Please carefully consider what you are planning to do.
I am unfamiliar with propane heaters that aren't the typical 'construction salamanders' that run off a propane bottle. I can say with certainty that if you have a portable propane heater that needs to exhaust combustion air to the outside, anchor the unit and the supply tank so it can't possibly move, and make sure any supply piping is installed so it will not leak. Make certain you have sufficient make up air to the firebox. Do NOT install any unit into a doghouse sized box to 'cover it up', for example. It takes ALOT of air to deliver btus to even a small residential furnace.
Make certain all combustion gas exits the yurt. Securely mount the vent pipe. To preclude blowback into the furnace, mount the vent pipe out the yurt well away from the dwelling, at a MINIMUM of two feet above the apex of the roof, if the exhaust pipe is less than 10' from the roof apex.
Not trying to throw a towel on your plan. Not knowing anything about the unit youi are planning to install might make what I've said here inapplicable. But whatever you do, think carefully before proceeding.