First point is correct, but not-sufficient. You also need a file named amxmodx-cstrike-0.20-RC7.zip :
http://prdownloads.sourceforge.net/a...e-0.20-RC7.zip
The same - unzip all to addons in cstrike folder.
Then You need download all CSDM package:
http://www.tcwonline.org/~lambda/csdm/csdm_mod.zip
For CS1.3 there is a separate package:
http://www.lambdacore.net/csdm/csdm_mod13.zip
Unzip this second to addons/amxmodx
But I'm not sure if my files will work for You with CS1.3 - try to use first this original package for CS1.3 (but bots will not choose any weapon). Then try to use my files (Your point 2 and 3). Let me know if this will work for You.
About this setting - for non-steam (but You have Steam) need write the line in amxx.cfg:
csdm_steam 0
But You - if You use Steam - You have to keep the default (csdm_steam 1) - don't need write in anywhere.
If I'll find time I'll try to compare what Bailopan wrote different in both version (for CS1.6 and for CS1.3). Then probably I'll re-write this version for CS1.3 to make support for bots (I suppose my version will not work for You). Can't You use CS1.6? It would be much easier for me to help You.
[EDIT]
I've just downloaded this CS1.3 version of CSDM , but there is no sources (sma file) - so I can't compare it with the source of CSDM for CS1.6. It means I can't help You.
Try to search at amxmodx forum - maybe there are some sources of CSDM for CS1.3. Currently I don't have any idea what the differences can be there between these vesrions (probably some weapons).
Another thing - I suppose in CS1.3 You don't have famas and galil weapons so however You will need to use
csdm_steam 0
if You will try to use my files. Sorry for my bad reply before.
[/EDIT]