Oh, I used to do that with wheat for our chickens in winter. I'd sprinkle a single layer in a flat plastic container with a ridged bottom & a lid, moisten it with a little water (not so much that's it's swimming) & cover lightly with a paper towel to keep the grains moist. I'd put on the lid and check it every day, adding a little bit more water to keep moist. If needed, you can tip it back and forth to make sure the grains get moistened. In just a few days it would have sprouted and I'd feed it to our chickens. They LOVED it and it really boosts the nutritional value. I should get back into that - thanks for the reminder!
BTW, you can buy sprouters, but they don't have that much room, and who needs an extra, unneeded expense?