I have a Ford Expedition XLT 1998 and my starter went bad how do I do the work myself.....will it be very difficult and is there steps that will help me successfully complete the job.

have you checked the starter relay...go to the owners manual locate it and exchange with any other one...same type...maybe is more simple than changing the wrong part

IF you have the necessary tools, a starter replacement is not a hard job to do. You need a SAFE way to get the front of the car in the air so you have enough room to get under it. From there it is only a matter of 3-5 bolts/nuts and it is off. Reverse to put it back together. I find taking a series of digitsl photos of things I am not used to before I start work gives me a source to check where things go. Go to your local Auto Zone, Advanced Auto, etc and tell them you want a rebuilt started. Most of them will give you excellent directions on what you need to do to change it out.