there are still people playing online? are there good bots for mp?

Yes; I don't know.

this has server browser or is ip connecting or i have to donwload a launcher for browser or how it goes?

Best place to find servers (if you don't feel like digging for pickups in IRC or on forums) is http://www.quakeservers.net/

QuakeWorld servers: http://www.quakeservers.net/quakeworld/servers/
non-QuakeWorld: http://www.quakeservers.net/quake/servers/

You can get the server's address from those lists, and then connect directly to that address using the Quake console or multiplayer menu.

Or if you use a modern multiplayer-focussed Quake engine like ezQuake (for QuakeWorld) or ProQuake (for non-QuakeWorld) then they will have a server browser included in the menus.

=====

For bots, see http://steamcommunity.com/sharedfiles/filedetails/?id=123626484