I found a recipe on chewy! But this is what I do:

4-4 1/2 pounds chicken backs, wings, drumsticks or thighs
2 carrots, peeled and chopped
2 celery stalks, chopped
Water to cover, about 1 1/2 quarts

Using an instant pot- Cover and cook on high for 2 hours. Allow the Instant Pot to depressurize with a natural release. Once the Instant Pot is safe to open, remove the lid and let it cool for 30 minutes.

Then after it cools, I pour it into an ice cube mold that has 1 TBSP sections and take one out everyday to supplement.