Backyard Ultra Race/Training Advice

As the title says any advice on training for and/or running a backyard ultra for a first timer?

Background: I’m one of the “started running during covid”people. No longer morbidly obese and enjoying the hobby a lot! After my first marathon last October I decide to try a 50k in 2023 but have now transitioned to the idea of a backyard ultra with an 8+ lap goal.