Hi Airen,
10 years ago, we directed Airen to see meet Seung Gi at the Festive Grand Theatre in Resorts World™ Sentosa for 2013 Lee Seung Gi “The Brilliant Show “ In Singapore. 10 years later, we are back at Resorts World™ Sentosa but a bigger venue, Convention Centre. Let's begin!
Please note that Sentosa is an island, a short walk away from Singapore's mainland.They also provided links to the MRT maps.
HOW TO GET TO RESORT WORLD SENTOSA, CLICK HERE- > http://www.rwsentosa.com/language/en-US/Homepage/HowToGetHere
A commonly used mode of transport to Sentosa is via the Sentosa Express (a light rail system).
Please refer to this for more information: https://www.sentosa.com.sg/en/getting-to-sentosa/
Sentosa Express is located within a shopping mall, Vivocity. Below is a photo guide on how to hop on the Sentosa Express to RWS.

b) At level 3, you will see the Sentosa Express entrance

c) If you have an MRT Ezlink card or Credit Card/Master with Ezlink logo behind the card, you can use it to take the ride. It will deduct $4 (round-trip) from the card. If you don’t have any of the card, please purchase a ticket using the steps below.

d) Head over to the ticket counters or the self-purchase machine to purchase sentosa express ticket.

Step 1: Purchasing your ticket. 1 ticket - $4 (Singapore Dollar).
Step 2: Click [$4.00 Island Asmission]
Step 3: Click the number of ticket you wish to purchase. 1 person = 1 ticket
Step 4: Get ready to put in your money when you see this screen.
Step 5: Insert your money
Step 6: Collect your ticket =)
e) Taking the Sentosa Express. Enter the gate by tapping your ticket.

g) Please alight at the Resorts World Sentosa Station. It is just 1 stop away.
Upon reaching Resorts World Sentosa Station, you are now at Resorts World™ Sentosa.
Please follow the steps below to get to the Convention Centre.
Exit Resort World Sentosa Station and walk straight ahead, you will find 3 twelve cupcake stores on the right.
Walk straight and turn right and you will see Universal Globe in front of you. Take the escalator down.