Facepalm

You may want gloves for this one...

Assuming you don't have a manual to read: First, start with a freshly -emptied clean dishwasher, no spills in the bottom. Wear rubber gloves if you're easily grossed out. Pull out the bottom drawer. Look in the bottom, you see anything that looks like you could turn it 🛞, with maybe a couple arrows ▶️ ◀️ to line up? Lefty-loosey it, pull it out and take it to the sink, along with any screenlike thingamabobs that come out with it. Run warm water and use hands, sink brush, or scrunge to gently remove all the gunk. You don't have to abuse it, you want it to last the life of the machine. Also feel in the hole, removing any gunk left behind. If the filter pieces come apart easily, do that, but put them back as they were before reinserting into the machine. Fit it back into the hole and righty-tighty to match up the arrows. Don't over-tighten! Go rinse out your sink, dry your hands, and set a monthly notification on your phone. It's much less gross if you do it monthly.