For part one you will have to go the the discussion section as ning will not allow me to post two parts at once
Part two of two.
By determining how long and wide the door needs to be. A normal and good working size for rails and stiles is 2" outside of the cut door profile that is cut by the stile and rail cutters. The best door is made using 13.16 thick material as this will give you a good edge on the inside when the profile is cut and should be cut so that there is a thick (1/8" and thicker if possible. But should be centered at the middle of the material edge.) That is the reason for the 13/16" material as it thicken up the weakest part of door that often gets cracked out from the weight of the panel exerting its force against the rail and stile profile when it is opened and or shut. Since the door frame suddenly stops depending on the speed the door is shut will generate a lot of force and because of the laws of physics anything that is loose will continue to travel and the same speed until something comes into contact with the moving object and stops it by overcoming the force at which it is traveling. In the case of the door it is the thin frame that holds the door panel that has to withstand the force.cause by it being shut. The door with a light panel will not have as much energy as a thick door panel because of its weight, but will also rattle and respond with a sharp rap sound it is shut hard. The heavier panels such as a raised panel with carry more energy that the thin panels and will respond with a dull sound and puts more stress onto thin frame that is cut into the door but the pattern bit as it cuts the grove and decorative door edge that you see around a doors inside edge.
Now we must know the depth of the cutter and I will use my bit set as an example. It cuts a 7/16 '' deep groove. Now for an example the normal overlay of a door is 1/2 inches on all sides and top and bottom. Measure the height of the door opening and for example we will use the measurement of 21 inches and the width is 16 inches, This is the measurement of the inside of the opening.
You will cut the stiles at 22 inches which gives the overlay of 1/2 inch on the top and bottom. The stile should be cut to 22 inches and 2 &7/16" inches wide.
The rails are next to cut. To figure them now you have to take the inside width of the door top and bottom width at the inside. Which was 16 inches,and add the 1 inch for the overlay (1/2" one each side) making the width of the door at 17 inches but now you need to subtract 4 inches from the inches because of the width of the two rail widths so that would be 17 inches minus 4inches giving you the rail length to cut at 13 inches. You will need to cut two rails at 13 inches long and 2 & 7/16 wide. There is one exception to the measurements and that is if you was going to make an arched door. In this case you would change the width of the top rail to be 4 & 7/16 inches high. This because of the height needed for the arch that is cut in the top rail. Making an arch is another total phase in making the doors and if anyone wants to know how contact me for directions. It requires additional bits and templates. I also have ways of cutting glass panel doors that have the arch plus building the divided light both the true divided and the single pane that looks a like a divided light
Once the rails are cut, put the cope cutter into the router and using some hardwood scraps set it so that it cuts the end of what would be the bottom and top rail with the cutter cutting a 1/4 thick inch tendon dead center in the piece. Once it is cut then install the profile cutter in the router and without moving the height of the router use again some scraps and cut the profile or and groove in a piece of what would be all of the pieces of the intended frame. Check the results of the cuts by assembling the piece together. Keep trying and once you have the setting right so that they go together with a flat surface left on the top and bottom then repeat the procedure beginning with the cope ( cutter that cuts the tendon) cut all four ends of the rails. Again with out moving the router height setting cut install the pattern bit that cuts the profile and groves and cut the inside of the four pieces. you are now done cutting the frame on the inside of the frame. Keep the scrap blocks with the correct cuts for fast set up next time you wish to build some doors. Noter: In order to be able to set the bit once and it is correctly set the router shanks must be equal length. It will not work this way unless they are and means that you will have to adjust each bit east time to the proper height.
Always cut with the good side down and set the depth of cut using the bearings on the the bit and set flush with the fence .
Cut the panel length 4 & 1/4 inch less than the doors height and 4 & 1/8 inch less that the width of the door. This give you the correct expansion gap around the door. Assemble the frame using glue and clamps and use a product called "space balls" in the groove around the door frame with two in the stiles and two in each rail. The prevents the panels form rattling and moving under weather and use. Clamp and check for it being square using the corner to corner method. Allow to dry and apply hinges. I have posted this on the community before so for detail check it out as to how to build a jig to bore holes for European hinges. I posted several articles on building doors and there is a posting on you tube that I posted with a slide show on building arched panel doors as well as several photos on my page. I will attach the link to the slide show on You Tube at the bottom of this post.
Questions feel free to contact me.