Q.growing ginkgo trees
I live in a northern suburb of Denver. I would like to grow some ginkgo trees. I bought saplings and placed them in well-draining soil. They all died. Is anyone familiar with their growth and what I may have done wrong?

Gingko trees do need a full to part sun locations with a rich loamy soil.
Watering is key to the start of a new planting and Gingko Tree's need regular irrigation until they mature.
This article will help refresh you on the care requirements.
https://www.gardeningknowhow.com/ornamental/trees/ginkgo/ginkgo-tree-care.htm
Remember that a reputable garden center or nursery will generally guarantee a new tree or shrub for the first year.