Here's a good place to start.

Michael

Here is a link that might be useful: Mortising hinges

Thanks Michael, but I can still use more help on the total job rather than just the mortising.

Here's a link

Here is a link that might be useful: door hanging

On your new door decide what is the top of the door. Example on a six panel door the small panels go to the top. On a slab door the top may be marked if it isnt then it will make no difference.
I have hung about 100 doors as a repair not construction. I will try to help you as best as I can.
With your old door in place check the fit. Most fits are OK. Fit is the reveal on the top bottom and sides of the door. With the old door still in place mark it top and back. The back is the side with the hinge pins. Mark the new door top and back this is for your reference it is very easy to get turned around doing this. Pull the pins on the old door and remove all the hardware including the hinge leafs. Do not remove hinge leafs on the door jamb. Measure the old door and cut the new one to that length be careful not to splinter the new door, score the door or clamp a piece of scrap wood on the side where the saw blade leaves the wood.
Set the old door on the side with the hinge mortise up. Line up the new door at the top of the old one. The back of one should be against the front of the other. With a combo square scribe the mortise of the old door to the new door. Now take one of the hinge leafs and trace the hinge between the mortise lines you just drew remember the pins on the hinge go to the back of the door. The hinge leaf is probably marked on the back side from paint or varnish, use this line to guide you when tracing the hinge. An interior door is 1 3/8"The hinge will set about 1 1/4" across the door. Use a router to cut out the mortise if you use a chisel be careful cut only across the grain of the door style or you will split it.
Install the leafs on the new door with only one screw on each leaf make sure to drill a pilot hole for the screw or you WILL SPLIT the door. If the door has 3 hinges , leave the middle one off until you fit the door.
Place the new door in the jamb put the top pin in first then the bottom pin, you may have to adjust the bottom leaf a little tap it up or down to make it fit. ThatÂs why I use only one screw at first. With both pins installed, drill your pilot holes and put in the rest of screws in the top and bottom hinges.
Put a screw on the front of the door where the knob will go, you need the screw to pull the door closed so you can mark the door where it hits the jamb. Remove the strike plate off the door jamb. With a pencil mark the door where it hits the jamb. Remove the door and plane down to the line, take your time. You may have to mark the door 2 or 3 times to get the fit.
With a pencil, mark on the back side door casing, the center of the hole located on the door jamb used for the door lock Close the door and transfer the mark to the door. With a combo square use that mark to scribe a line on both sides of door about 3" long and across the style.
Now find the back set of the lock you are using. A new lock will tell you, if you use the old lock, measure the old door from the edge to the center of the hole. 2 3/8" and 2 3/4 are common sizes. Measure also the size of the hole you will need 2 1/8ÂÂis common.
If the back set is 2 3/8. On the line you drew on the door make a mark 2 3/8 on each side of the door. If the hole is 2 1/8, use a 2 1/8 hole saw, cut half way through the door and finish the cut from the other side do not plunge straight through you will splinter the door. Mark the center of style and drill a hole to fit the door latch use a small as possible hole to fit the latch you donÂt have much room to spare. Some latches need to be mortised to fit if this is the case put the latch in the hole and trace the face of it then remove the needed amount of wood and install it. Remember to drill pilot holes. Install the lockset and the third hinge if needed. Now wasnÂt that easy?

Good Luck, Woodbutcher