There may be previous posts on this subject.
Check the reference section also.
Have you tried looking yet?
Making Dag prints is just like making silver chloride gelatin prints.
Just don’t slide the Dag plate or transparency around or you will scratch the Dag plate.
As with the paper prints, you need to make test exposures to find the correct exposure.
You can use a regular incident light meter to measure the strength of the light coming though the transparency. Then, if you are familiar with optics, you can calculate the intensity of light hitting the film plane inside your camera. Or you can just stick your light meter inside your camera and measure the light you use to make an in-camera Dag.
For a first approximation, you can neglect the difference between UV and visible light here. Dags are sensitive enough to both blue and UV. Even if your light source is a regular incandescent bulb it has enough UV do the job. Use a blue photoflood bulb if you need lots of light for a Becquerel Dag.
You don’t mention the equipment you have but depending upon the strength of the light source, the exposure could vary from a few seconds to several minutes.
Sorry if that’s not precise enough for you, but you need to provide more info.