Hey @akomaring!
Normally it is quite hard to get the hyperelastic parameters. For general info. about them, please see our documentation here: Hyperelastic materials. For detailed study, please see: ABAQUS theory documentation (Please see section 4.6).
If you want to have the constants for specific model, you can pass over the stress and strain data of your material and I can compute it for you.
Best,
Ahmed