If you are looking for the ei only then a series of exposures that range from 3 stops under the meter reading to 6 stops under the meter reading in half stops should be adequate. Leave one or two frames (with roll film and 35 mm) blank. If you are testing sheet film, toss in an unexposed sheet. Process as normal. Now after the film is dry, use the densitometer to determine film base + fog by measuring the clear frames or clear sheets. Write that number down. Now measure each frame and find the frame that will be the nearest the .10 density. This number will be the ei of that film. Don't forget to subtract the film base + fog and then find the .10 density. keep good notes so you will know what frame is what.
To find the development time, we are interested in the frame about 3 stops over the meter reading. Run the test and start 2 stops over to say, 4 and one half over. Process the film at the manufactures published time. Using the densitometer, find the density that is closest to 1.20 for condeser enlargers and 1.30 for diffusion enlargers. If you are way under processed or way over processed, then another test is needed. Way over is generally the problem. Start to process the film and reduce the process time by about 20%. Read the film and adjust as necessary. Pretty simple if time consuming.