It’s a deathmatch map, so the only objective would be “frag the enemy”.
Have you actually made a level? Since every level needs it’s own script, you could copy snippets of other scripts though.
A script is not necessary if you don’t use it. It’s only there to allow a mapper to do stuff in ‘runtime’, whilst the level can only be changed at compile-time. The script allso allows things you can’t do with level entities alone, like keeping variables, checking different things going, easier animation, etc.
The .objdata is a file to put you’re objectives in. I believe however that you need a tiny script file to set the number of objectives. Then the .objdata gets read and will be put in the player’s limbo menu’s. How to make these files can be found by using the SEARCH button or looking in the large sticky in this forum!