Activate Overgrown Estate by sacrificing a nontoken Forest, which is a creature due to Ambush Commander.
When the Forest dies, Yedora triggers, returning the Forest from your graveyard to the battlefield face down as a Forest land.
Resolve the Overgrown Estate ability, causing you to gain 3 life.
Repeat.
This ingenious loop turns your own real estate into a renewable life-source by letting Ambush Commander animate every Forest you control into a living Elf creature. Once your lands can walk, you can feed one to Overgrown Estate to gain three life, instantly triggering Yedora, Grave Gardener to rescue the fallen land and smuggle it right back onto the battlefield face down. Because Yedora brings it back as a fresh Forest, Ambush Commander's static ability immediately re-animates it into a creature ready to be sacrificed all over again, fueling an endless engine of life and triggers.