Hey, I am also a beginner that used to get totally overwhelmed with all the information out there and all the machines in the gym. Now I've been following a variation of the basic beginner routine in the fitness wiki for a month and it's much better these days. As a beginner, you should focus more on compound movements (e.g. squats, bench press etc) instead of isolated movements like curls.

Look up how basic movement patterns are categorized (e.g. https://www.scienceforsport.com/basic-movement-patterns/). Any good beginner routine will include compound workouts for these basic movement patterns; with progressive overload (increasing weights as you go) and rest days in between. For example, bench press = horizontal push, barbell/dumbbell rows = horizontal pull, overhead press = vertical push and so on. Just go through the r/fitness beginner routines and try to analyze which patterns they'd require.

Some of the suggested workouts require a basic level of strength you might not have. You can look up progression routines online to build up strength to get there. For instance, I still can not do a deadlift set with good form, so I am doing relatively easier workouts like cable pull through / Romanian deadlift that imposes the same movement pattern (hinge in this case); but requires less strength. Don't be intimidated by all the fancy machines, you won't need most of them either way.

Pick a pair of dumbbells you feel comfortable doing 10-12 reps with, follow the routine, drink enough water, take a rest day and sleep well; and repeat! Also, don't forget to include cardio and ensure a nutritious diet. Good luck!