In SU, “flipping” has a specific meaning, namely, to replace a selection with its mirror-image opposite. Flipping essentially reflects an object 180 degrees along an axis of your choice. What yoiu want to do is simply rotate an object ninety degrees.
There is only one Move tool, and as it happens, it does have a provision for rotating groups and components. Notice that when you hover over the face of the bounding box of a group or component with the Move tool, each face of the bounding box sprouts four small crosses at the midpoints. You can use any of the crosses as a handle to rotate the object around the axis of that face.
Alternatively, you can simply use the Rotate tool to stand up imported linework. You should do some intensive boning up on the Move tool and the Rotate tool.
You should also bone up on Layers. The term in SU does not mean whatever you mean when you use it.