Just as AAway has stated, arrive a little early to check in and go into the lounge. After 9:30 pm, the security lines at TBIT will be a few hundred people long (no joke here) due to the number of flights leaving. Avoid this by checking in early.
First class lounge will be a moderate size room within the business class lounge. It will be on the fourth floor on the north side of TBIT (or right side if you are facing the terminal). Take the elevator after passing the security.
The food will consist of cheese and cracker plates, sandwiches if i recall correctly, instant noddles (try the shin ramen, it is really good!) and chips that are exclusive to F lounge.
The view of the lounge is also excellent, as it is situated right above the main north south taxiway, and you might actually be able to see your
MH plane go across it as it is being towed from the stand to the gate!
It is truly a comfortable lounge and will be worth coming two-three hours early to check in. Enjoy!