When not sure what to do or how to start just pick a moderately heavy pair of dumbbells, then without thinking, immediately start with first random exercise which comes to mind. It doesn’t matter which exercise or why, just start and then for the next 5 min you are not allowed to put them down.
Keep going from one exercise to the next every few reps, you can even just carry the dumbbells around anyway you want but don’t stop moving, do something but don’t put the weights down.
Those five minutes of random moving, carrying, pushing, pulling and pumping with a pair of dumbbells is all it takes, to transform you from being indecisive, to motivating or even warrior like mindset, to follow up with a proper workout.
Do not underestimate the power of five minute transformation. Similarly too getting out of bed when you are sleepy, a lot of times the hardest part of your workout is to start the damn workout. Have your dumbbells ready, commit for 5min, it can change your life.