I need some info, diagram, or something to let me know how to hookup a sewer line for a 3 bedroom 14 x 70 mobile home.

The drains on the home are all in place when you buy them so you just want the home main to the city sewer or septic, right?

Yes, there should be a main 4 or 3 inch line that comes out of the mobile home, and it connects to the main ?

I need some info, diagram, or something to let me know how to hookup a sewer line for a 3 bedroom 14 x 70 mobile home.
Your unit has a discharge pipe coming out of the sub-floor. You will connect a PVC pipe to the lots sewer system using shielded couplings, (see image).
Good luck, Tom