There are 2 kinds of maps.
1 - Hostage Rescue (CT rescue hostage by taking them back to buy point)
2 - Bomb map (Terrorists plant and set off bomb while CTs try to diffuse it)
As for who is an enemy and who is friendly, it just takes time to recongize all the skins.
You can set buy scripts to buy specific load outs at the beginning of each round. CS:Source lets you buy your last loadout. I'm not familiar with setting them up I just became familiar with the buy menus.
Best thing to do is learn the maps. When dead ghost around the map to find out where everything is.http://www.counter-strike.net/manual.html
has an old manual. Some stuff is out of date (Escape/Assassination) but Hostage and Bomb info should be good. Was trying to find a better how to but havent yet.
Dont worry about dying a lot. I haven't played CS in months and almost all I did was die when I played a bit last night. On one map I had more kills in one round than the previous 2 maps I played because I couldnt kill squat.[/url]