Hi, fprefect,
Click on the link below and you will see a schematic of the Ortgies pistol. As far as I know, they are all the same. Parts 5, 6, and 7 are the only three parts in the area under discussion, and they go together exactly as shown.
http://www.e-gunparts.com/products_new.asp?CatID=3728
The firing pin spring guide (5) has a groove under the head and the firing pin spring should have the end coil crimped to fit into that groove so the parts stay together.
It is a good idea to expand the first coil at the front of the firing pin spring also, so it fits tightly into the firing pin. That keeps all three parts together and allows them to be removed/installed as a unit.
To assemble, you put the firing pin in from the bottom of the slide (it won't fit through the hole in the rear) fitting the lug on its side into the cutout in the slide. Then you install the firing pin spring (open end forward) into the firing pin, and push the firing pin spring guide forward, compressing the firing pin spring, until the head of the guide can be pushed into that slot in the inside top of the slide. Then the recoil spring can be put on the barrel (it also has a tight end that goes over the barrel to keep it from jumping away), and the slide brought back and down. If the cutout in the slide or the firing pin spring guide is worn, the guide might not stay in place, but both can be reshaped if necessary.
(I will note that those firing pins are subject to breakage, so always use snap caps when releasing the firing pin. Also because of frequent breakage, gunsmith made or home made parts can often be found in those guns. Some are OK, but others are not and may be dangerous.)
Hope this helps.
Jim