How to change out transmission oil for a standard 5 speed on 1998 GMC Sonoma

When i was driving my truck a week ago on the freeway
it started boging down and was kinda doing a jurking motion.I got it back home and the next morning i noticed
a big patch of oil.and know when i start my truck i get
a fairly load noise under my truck coming from the trans-
mission,this happens every time i start my truck.

Asked by for the 1998 GMC Sonoma