If you don't have a DME to allow you to fly the correct CDA, then get to the MDA ASAP, PF level off, PM eyeballs out looking. If you fly into the PAPI from below, well and good, do it and land. If you get visual too late, GA and have another go. No point in a CDA if it doesn't take you to the runway
on the correct 3° slope. You've got to have a DME (or a GPS distance in lieu, or of course a FMS DB approach) to make a CDA work.
Configure the aircraft, and just before the FAF you preselect your FPA (-2.6 degrees here) and when you want to start down you pull the knob and you will get 2.6 degrees down.
Exactly when you pull the knob is a complex subject and will vary by type, available aids and maybe some more accurate points that you can generate yourself (more accurate than a marker beacon).
You can vary your FPA on the way down to keep in line with your height/distance checks. On this NDB there are none, so you have to just maintain the rate.
When to pull is the problem. No DME? You're only guessing.