1998 Isuzu Trooper Replacing entire exhaust

1998 Isuzu Trooper 6 cyl Four Wheel Drive Automatic

I need to replace the exhaust system but the shop doing the work is having trouble getting the passenger side cat pipe off the vehicle they have it broke loose and stripped a exhaust manifold stud in process which now they have to replace and they removed the cross member and broke off all the bolts getting that off, in all fairness they were very rusty and old, but how does this thing come off and how can the new one be put on what else has to be removed to facilitate this. And do I need to make another donation each time I ask a question to get an answer? And I think they gave the wrong 02 sensore one is idintical to passenger side but the other was in same box but had diff connector is the driver side upstream diff than the passenger downstream.