Ok, here is an easy way to install maps. First you need a copy of WinRAR.

Then you need to open the .rar file you just downloaded, and extract the map information to your cstrike folder.

This is located in (drive):valve/steam/SteamApps/Acct name/counter-strike/cstrike.

If for some reason it doesn't work then you might have to manually extract the files.

1. Create a folder on your desktop that is easy to find and name it however you'd like.

2. Extract everything to your unpacked folder.

3. Go into your root cstrike folder .... (drive):valve/steam/SteamApps/Acct name/counter-strike/cstrike.

Here you will see a bunch of folders and other files . We are concerned with the following:
Maps
Gfx
Sprites
Sound
Models

If you don't see these folders then you need to create them.

Simply cut and paste everything from the unpacked folder into the appropriate folder. Here is a simple guide:

File Name                Folder Placed In

.txt                                    Maps
.bsp                                 Maps
.tga                                  Gfx/Env
.wav                                 Sound/ambience
.spr                                  Sprites
.mdl                                 Models

If you get any .wad files, place them in the ROOT cstrike folder ... (drive):valve/steam/SteamApps/Acct name/counter-strike/cstrike.