Ahhhh! I used to spend hours playing that game when I came back from primary school. Star Trek in ASCII. Brilliant.
There should be a help file somewhere with all you need to know. Read that.
The Phasors are the best weapon you start with for dispatching bad guys. The Torps use less energy but they can stop working very easily if you ships gets banged up a bit.
If you shoot a star with a torp the explosion may take out a few ships, but you will loose points at the end of the mission.
If you raid some enemy supply stations you can get some plasma weapons. They are GOOD! Just don't use them at short range or the blast will kill you.
Then there is the Death Ray... It's suppossed to be the best weapon in the game. Thing is I've never been able to use it without half my crew being turned into hideous mutants.
Warp around a lot. Try not to engage more than 2 enemies at a time. If reinforcements arrive LEAVE.
I really should reinstall it. Too much fun.