Many of your programs install in the normal way...
The various Scenery Add-Ons appear in the FS 2004 "Scenery Library" when the Sim is running, Their order can be re-arranged there, if necessary.
There is a preferred order, but I generally find everything seems to run OK as I install each one, working downwards.
See how it runs...

...!
Paul...G-BPLF...FS 2004...FS Nav... 8-)...!
Win 8.1 64-bit. DX11. Advent Tower. Intel i7-3770 3.9 GHz 8-core. 8 GB System RAM. AMD Radeon HD 7700 1GB RAM. DVD ROM. 2 Terra Byte SATA Hard Drive. Philips 17" LCD Monitor. Saitek Cyborg X Fly-5 Joystick. ...and a Briggs and Stratton Petrol Lawn Mower.