Only a stone’s throw away from Raffles Place MRT station; simply take the route of Exit F/E and from there follow the river and tada! You’ll be able to see the majestic building in no time!
Seriously, I doubt anyone will take a bus when you are wearing gowns or tuxedo suits. But oh wells, for the benefit of your doubt, there’s a bus stop just right in front of the hotel.
Well, obviously this is the most sensible way to get to the hotel without sweating and exposing your newly bought suits and gowns to the dust and dirt off the road. Below is a map of area, just for your reference ya?