I would always suggest having a mechanic do things first and only try yourself if you think you can do it and you do not have the money for a mechanic that can give you a warranty.
Disconnect the battery cables in order to reduce the possibility of accidentally shocking yourself.
Remove the electrical connections from the side of the starter.
There are usually two wires: a positive and a negative wire. Remove the
positive wire first, and then remove the negative wire from the
starter. You may want to mark the connections with a paint pen to help
you correctly reconnect the connectors to their proper terminals. To
remove the connections, you'll need to use an open face wrench or socket wrench
to remove the bolts.
both of the electrical connections are removed, you'll need to unbolt
the starter from the chassis. Before you remove these bolts, take note
of how the starter is oriented. You may want to mark the bolts with
paint pens. There are usually only two or three bolts that attach the
starter to the vehicle.
Remove the starter. In preparation, look closely at your car and
determine what path will be easiest for removing the starter. It might
be a tight fit, but you'll need to twist and pull the starter around
various engine and frame parts in order to get it out of the car. Some
cars may be particularly tight, especially those with front wheel
drive. You may have to remove other parts in order to get enough space
the pull the starter out. If you do remove engine parts, take care to
remember their proper location. Replace bolts into the same place they
came from once you pull a piece off. This will help you keep up with
all of the pieces.
Once you've pulled the starter out, you can put the new starter in its
place. You'll need to put it back in the exact same way you pulled the
old starter out. Once you have it in place, put in a bolt just enough
to hold the starter in place. Then connect the electrical connections
beginning with the ground wire. Once the ground wire is connected,
attach the rest of the wiring. Next, install the rest of the bolts
holding the starter to the frame. Check to see that all bolts are tight.