You have to join a server with other people on it.
After starting the game select “play online”.
Then you get a table with servers (make sure you have PunkBuster enabled (right bottom)).
Select a server with other players on it and which has a good ping.
After joining a server press “L” and select a team and a class.
Only the engineer has dynamite.
The other classes have some other goodies.
There’s also a document included with the game.
You can find it in:
path2ET.exe/Docs/Help/Manual/default.htm
You can open it with every webbrowser.
You wiil find the answers for most of your questions there.
If there are still questions open feel free to ask.
The forum has also a search function:
http://www.splashdamage.com/index.php?name=pnPHPbb2&file=search
So it’s also a good idea to search the forums before posting.
There also some external server browsers evailable that might be more handy.
For example I use the “All Seeing Eye”.