HI Mercedes, here’s a good tutorial: https://www.bhg.com/homekeeping/laundry-linens/tips-checklists/how-to-clean-washing-machine/
I use Affresh from Home Depot.
I use Affresh, as well. I also have a "tub clean" cycle on my washer and will occasionally use vinegar in the detergent cup then run a wash cycle. I hope this helps!
Run bleach through the cleaning cycle, then again with nothing. Wipe all gaskets and areas with diluted white vinegar.