Welcome,
Step 1 : Dismiss Johns recommendation to drill (it was funny though).
Stem 2: Call the installer and complain. Be nice at first. If nothing better can be had, try to negotiate for him to lend you what you need to clean it up.
Step 3: Follow Tkanzler's two words. But if you cant find that, any small submersible pump will work, even a larger powerhead for an aquarium or a pond pump. Get a flexible tube long enough to reach to the sink (or deck, or even to a bucket). Set the pump in the deepest bilge area in the aft birth and pump the water out till the pump starts to run dry. Repeat as needed. The bilge areas do generally drain into each other on this boat, but not from port to starboard unless the water level is very high.
Step 4: Have a Beer.
Step 5.Clean up the remaining water with sponges or towels. Repeat Step 4 as needed.
Eventually purchase two nice large rectangular sponges and a turkey baster. This will be your bilge pump. Place one sponge in the bilge area under the starboard side cooler liner. Take out cooler and liner, you'll see the "starboard bilge" , or at least my

"bilge" as dictated by my boat load with the boat in the water, YMMV. The port bilge is under the galley area single seat.
Monitor the sponges regularly. If the boat is in great shape the sponges will stay bone dry. if yours is like most of ours (you know who you are), you are likely to find a sponge-full or two following a rainy period. Squeeze em out, and put em back. Occasionally you may even need to turn to the turkey baster and a cup.
One last thing, you may want to consider draining it and re-flood it with clean water and some cleaning solution and drain it again. Then rinse . repeat... like shampoo.