In order to find your working set weights, please warm up by following these guidelines, and remember that you only have to use approximate rep max loads, so don't worry about knowing your exact rep maxes, just "in the vicinity."
Do your 30 rep max for 12 reps, rest a minute. Example: 100 pounds for 12 reps
Do your 20 rep max for 8 reps, rest a minute. Example: 130 pounds for 8 reps
Do your 10 rep max for 4 reps, rest a minute. Example: 150 pounds for 4 reps
Then choose any load in the 5-30 rep range (reference rep range article here) and begin the working sets, resting as much time in between each set as gets you breathing normally and feeling strong again. This is how you warm up and choose loads for the first exercise in your daily session. For all others, you can just do the set of 8 and 4, or even just the set of 4 if you already feel nice and warmed up. Any weight in between your 5 and 30 rep max technically works for all exercises, but we recommend choosing mostly weights than challenge you in the 5-10 rep range for beginners and weights in the 5-20 rep range for intermediates.
If you're advanced and know about load-specific and exercise-specific SFR, you already know what you're doing! If you'd like to use different weights for the same exercise for down sets or drop sets, just click on "duplicate exercise" in the top right hand menu of the exercise you're doing and choose your new weights. If you'd like a deeper dive with slightly different suggestions on warming up and selecting weights, give these two videos on the topic a watch:
For more detailed information on warming up, check out the video below:
For more detailed information on setting your working weight, check out the video below: