In the past I have used this station a lot, in my early days, when I was still visiting Thailand as a tourist, to get to bus to Koh Phi Phi or Phuket. Later when I lived on Koh Samui I used the station as a start or finish point for overnight trains to/from Bangkok.

Entrance to the station
I prefer trains over buses in Thailand, especially considering these kind of stories. Accidents with trains happen a lot less and I sleep a lot better on trains compared to buses. The trains in Thailand for overnight travel offer 2nd fan and aircon bunks and 1st class aircon bunks. Comfortable enough to me, compared to a declining seat in a bus. However, ideally I fly nowadays or take my own car!

Platform 1 with a train waiting to depart
Opposite the station are plenty of food stall, small mini markets, a few budget hotels and plenty of travel agents that can arrange a bus and ferry connection to 'the islands', being Koh Samui, Koh Phangan and Koh Tao. Other than that there's not really that much to do, my advice is to bring a good book. Night trains for Bangkok tend to leave around 9pm but your arrive somewhere around 4 or 5pm at the rail way station! That can be a long wait.

The schedule
There are not that many trains arriving and departing in this rail way station, just 14 in total. They actually all fit on this one schedule board, which interestingly enough has space delays. Seems to happen with Thai trains!

In case you just show up, you can't miss the ticket booth directly after the entrance
In general I would assume that you would buy a combi ticket on Koh Samui for ferry/bus train.

These signs can be seen on all Thai railway stations

Station master
For departure, the system still relies on man power and signalling flags. From various wagons, employees hang green flags out of the window, indicating that that specific part of the train is ready to leave.

Once the all important whistles are blown, the train can leave

Outside the railway station
Riding trains in Thailand is convenient and a 'real adventure' with stunning sights. It's convenient as well, there's a food/restaurant wagon on the 'bigger' trains and don't forget, you're in Thailand, at each station you can buy food or people wills ell it to you whilst the trains is halted at a station. Give it a go, it's well worth the effort and time in my opinion.
Camille