Creating Complex Assemblies - Formulas and Values

Hi! I am working on creating and updating our parts and assemblies list in our Sage 100. I have the estimating module.  I work for a General Contractor doing estimating. I am trying to create assemblies to make this process quicker.

I understand the assemblies pretty well - add parts - the colored arrows - etc. What I don't understand is the Formula line for the assembly and the "value" line for the parts. The documentation on this is incredibly simple, and doesn't help me at all.

Does anyone have any insight on how these two fields relate?

Thanks for any/all help!