It’s simple. It’s just not fun. My Dad just did it for his neighbor last year. Concrete sawed and jackhammered the channels, hand bombed, loaded and discarded the concrete. Hand trenched and discarded the clay beneath the slab to the depths required for slope. Hauled in sand in pails for slope and backfilling. Laid and connected the pipe. Mixed and hand bombed the ready mix concrete. Repoured and repaired the basement slab. An ignorant, dusty, dirty, heavy job. Hundreds of trips up and down stairs with weight. He’s 80. I’d just fucking pay the Mexicans lol.