I don't know what model Daybreak you have. Yours may not be the same as mine.
I have a Daybreak 22GOc. The fresh water tank on my unit is under the driver's side Dinette seat. The valve is difficult to use/see as it is between the wall and the tank I made a tool to use on it out of 1in pvc grey conduit. The pump on my unit is under the other dinette seat.
There are also two valves under the coach near the rear bumper that are low point drains. you will also need to have those closed.
"Never promise more than you can give. Always give more than you promise."