To use compost in my garden, I dig a hole 12 to 18 inches deep. I fill the hole most of the way up with compost and plant tomatoes, eggplant and beans around the hole.
Early on, I water the plants directly, but I also put water into the hole with the compost. The plant roots grow toward the moisture and compost to feed. Last year, my tomato plants were 6 feet tall.