The rest of the sets are for those who understand schedules and there are 3x2.5k, 3x3k and 3x4k, the total distance and are written in metres.

All schedules can be adjusted to suit your own strokes and send off times.  Here is a longer example set to determine where you should pitch your training at:

Example set 2,000m- (1)
Warm up 200 swim mix
100 kick choice
200 pull free breathing every 3pulls
100 kick IM
Main set 8x50 free on 60secs
8x100 alternate IM/Choice + 20-30secs
4x25 kick free all fast +20 seconds
Swim down 100 easy

Look at the above and work out if you can fit this into your time at the pool, then look take a look at the other schedules.

You should have with you kick and pull floats, take a drink to keep your body hydrated. Use of a pace clock is an advantage plus a clear plastic sleeve to take copies of schedules with you.