The main window is the 3D viewport. This is your game world.
While the mouse cursor is in the viewport, hold the right mouse button to around to look. Use the W, A, S, D keys to move the camera. You can also move the camera up and down relative to the camera by using the Q and E keys.
Holding down the ‘Shift’ key toggles the alternate camera movement speed. This is useful for making fine camera adjustments when you are up close to an object.
To change the default or shift camera move speed, go to File -> Studio Settings -> Studio and under the ‘Camera’ group, adjust the ‘Camera Speed’ and ‘Shift Speed.’
The 3D Axis
Every physical object has a size expressed in length x height x width. In the real world, you might use feet or meters as the unit of measure of length.
Roblox’s unit of measure is the ‘stud.’
On the Baseplate template, each of the dark lines on the ground represent a length of one stud.
The 3D View Selector shows the X, Y, and Z axis. Like a compass, these are always aligned with coordinates of the game world regardless of the direction the camera is facing.
Clicking on a face of the 3D View Selector will pan the camera to align with that face.