Hi welcome
the best possible way would be building a relationship with a local farmer that has animals pasture raised 100% grass-fed and finished, never grain feed. the animals should not have vaccines, hormones, antibiotics or mRNA shots. Also best if you see the animal being slaughtered and visit the farm and see their environment.
thats the most optimal, 99% people wont ever get there.
I would suggest buying from the best farms or shops you have access and trying them, taste is important. If it tastes sweetish and good, then it should be ok, and doesnt smell bad. test many places and start eating the ones that look the best, taste the best and smell the best.
so just start calling the farms and shops, or best, call first and visit them, no shipping first.
I really recommend you beef liver, try to find it anywhere, its super healing.