Luxury Coach don't do Melaka to KL route.
As Habrosus said, take bus 17 or grab to Melaka Sentral buy ticket there or advance booking through easybook.com. I did advance booking for almost every things
but if you miss 1, you will miss all. That's why I very strict on timing.
I book Mayang Sari, the journey is about 2 hours non-stop, reach TBS.
Note that TBS is about 10Km to the south of Kuala Lumpur city centre. To get to the city centre, use one of these options:
1. KLIA Ekspres high-speed train (the non-stop airport metro line) to KL Sentral. 15 to 20 minutes interval.
2. KTMB's ETS trains. There are only 4 services a day running at fixed schedules from Bandar Tasik Selatan Railway Station (just beside TBS) to KL Sentral or Kuala Lumpur Station. These are northbound trains from Gemas to Butterworth or Padang Besar (on the Thailand-Malaysia border).
3. KTMB's older Komuter trains will also service between Bandar Tasik Selatan Railway Station and KL Sentral/Kuala Lumpur Station but at hourly interval.
4. Rapid KL's LRT networks covering Kuala Lumpur. Get to Bandar Tasik Selatan LRT Station (beside the railway station) and use the monorail to get to your destination. Changing of monorails may be required.
(The LRT station @ TBS is known as Bandar Tasik Selatan (SP15 Station).
I take LRT to Chinatown (Jalan Petaling).