use one hand (or fork) as the dry one and the other hand (or another fork) as the wet one. With the dry hand/fork take the onion ring and put it in the container with flour, coat it from all sides and then shake a bit to let the excess flour fall off. Then transfer the onion ring to the second container with aquafaba. By now using your wet hand/fork, coat the onion ring from all sides with aquafaba, then keep it for a moment over the container to make the excess aquafaba drip off. Then transfer the onion ring to the third container. By using again your dry hand/fork, first try to sprinkle some breadcrumbs over the onion ring to avoid that you touch it while it’s still wet. Then, when it’s slightly coated, with your dry hand/fork move it around in the breadcrumbs to coat the onion ring completely. Then transfer it to the baking tray. Repeat the same with all the remaining onion rings;