On the trenlii dashboard, the CMA you created will show under My CMAs. (in this example: 39 Natalie Pl)
Click on the CMA report you want to and hit the Edit button below.
Go to STEP 5 (Edit Comparables) It will show your Subject property and listings next to it. Click "Edit Custom Fields" (You can do the same for the comparables).
You’ll get a screen pop up that gives you an option to add fields. You can also delete the fields already added.