Try the app “Strong” and enter your hw into it (or have your trainer do it). You press “start” to begin a workout, then it dings when you need to start a new set, you enter the data (how many reps etc) and check a box, and start the next set, etc.
I find I just have to motivate enough to get to the gym, open the app, and press “start” and then I’m inclined to want to check the boxes / hear the song, and keep going at the proper pace without too long of a rest between sets.