The layoout is simple enough, each event is llike a little story, or instruction.
For instance, When mission time has elapsed>5>self destruct>GTVA colossus
Guess what happens 5 seconds into the mission?
Linking these and chaining is only as difficult as your organisational skills. You can use events to send messages if a ship jumps out AND your health is within a defined range between 50 and 75% for instance. Or you can make the sun explode if you re-arm with a full secondary bank, (i've done this before to mess my little brothers head up)
Just get used to the usage via the tutorial, Then play with the SEXPS. Its fun and a learning curve all in one.