You need to press the "Compile" button.
Look at the tabs of TrigEdit. There should be one that looks like this:
Now to change the properties of the unit, you will need to enable the current slot you will be using. So you will need to delete the ';' marks from the beginning of the properties that are going to be used.
For example, if you are creating a Terran Marine with properties, you will need to enable the HP slot (because Marines have HP). If you were creating a Protoss High Templar with properties, you will need to enable the HP (hit points) slot, the EP (energy points) slot, and the SP (shield points) slot. That is because a Protoss High Templar has all these things. Make sure you set the slots to the proper percentage value (not hit points amount, percent of hit points amount).
Now where the FLAGS are is where you will be entering the properties. There are 5 flags you can use on a unit. They are:
Now you enter these flags in seperated with a space.
To use these CUWP slots, you will need to refer to them in your trigger. The place where you write a number for the CUWP slot, you will write in the "Slot Number" + 1. This is because it is the first slot even though the it is labelled 0.Here you can see I am using a CUWP slot. I will refer to this slot as slot 1.