Hi, scripting is best learned just reading tute’s, and other map scripts and you’ll eventually figure out what’s going on 
oh, and g_scriptdebug 1 ;run your script till it doesn’t work, then /condump console_dump.txt 
-prefabs
For personal prefabs, what you do is build what you want to have as prefab, whether its a complex light sconce, or a shelf with items on it, its still the same. What you do is select all the brushes you want, and select file/ “save selection as…” and only what you have selected will be saved to this new map. Then you just use file/import to bring it into your “working” map.
If its a simple 3 brush thing, you can hit space to “clone” what you have selected. This technique is handy for everything from lamps to stairs.
-custom textures
when you extract the pak0.pk3 in /etmain(if you haven’t done that, do that; with winrar/7zip) you’ll see in the /etmain/textures folder how they organized their textures. So what you do is create a folder in there with “yourmapname” and when you go to pack the pk3/for beta/testing you only need to grab your folder for redistribution. At the same time, you need to add “yourmapname” to the bottom of your shaderlist.txt, its in your /etmain/scripts/shaderlist.txt
Now you can create your shader file, named “yourmapname.shader” and start using custom shaders too. (Do a search on shaders, you’ll find loads of info) Once nice thing with custom shaders is you can create new effects with the default textures already there.
I’ve spent many hours playing with alphashadowed blood, and lighting autosprites for example.
gl in your study
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