Well, under normal circumstances this would be a trivial operation using the move tool. Select the thing you want to move and drag in the direction you want move, then type 100cm, done.
However you are modeling without using Groups or Components which is a very difficult way to work. This means that all your geometry is stuck together and it’s very difficult to move or alter any one thing without effecting everything else. In a normal workflow, every individual piece of your model would be a made into a component or group as soon as you make it. In sketchup, all geometry is “sticky” and will naturally stick to everything else, this can be very useful in making certain shapes and altering geometry in a controlled way, but not everything should stick together, we put individual pieces into “containers” of groups or components to keep them from being sticky so we can move them around as units. A container for the floor, a container for the walls, one for the pool… this makes it possible to alter any given part of the model later easily.
In your case it will take some very tricky and careful selecting work to isolate the pool without damaging the rest of the model. It might be easier to erase the pool and redraw using groups and components.
• SketchUp Help Center : Organizing a Model
• SketchUp Help Center : Controlling Visibility with Layers
• masterSketchUp.com : Sketchup Layers vs. Groups & Components