how to change engine mounts and exhaust plugs

[rolandhaasnc@hotmail.com]

Hi Guys, I bought a challenger 1996, and the previous owner told me that he got qouted to change one of the front rubber engine mounts and also that I had to also change the exhaust plugs " weld them?" all this in French so something might be lost in translation ;-).
I downloaded the workshop manual, and have started looking through that and tommorow I will get the rubber engine mounts what I wanted to know was what is the best way to change these rubber mounts ? thanks for any help on this
cheers
roland