First Run of Radiant

• Opening Radiant for the first time

1. Double-click on the "CoDRadiant.exe". 
2. It should bring up the "Open" window, it ask you to open a file with the .qe4 extension. There's a file called "COD.QE4" in "tools" folder. Open it.
3. Now you're running Radiant, go to "File">"Project settings" and make sure you have the same destinations as mine and do any important changes.

Basically; 

basepath (.EXE location) is the location of your CoD1 game.

mapspath (.MAP location) is the location of where your map files will be saved (I suggest you to keep it in tools>bin).

rshcmd says; "..\bin\" in case you couldn't see it. (without " ")

remotebasepath is again the location of your CoD1 game.

entitypath says; "..\bin\cod.def" in case you couldn't see it. (without " ")

texture dir keep it as "textures. (without " ")

     4. Click "OK". 

     5. Now, click on "Textures" and check if all these show on your screen.

     6. Now right-click on the white area of the program (the smalled boxed area) and check if all these show on your screen.

     7. While you're still there, move your cursor to "mp" and check if all these show on your screen.

If something of the above doesn't show, try checking your "project settings" again, sorry but I can't help anymore with that.

Now, you're ready to start mapping!