NetRadiant's two main methods of viewing, creating, and editing objects are the 2D view and the camera view.
NetRadiant uses grids to simplify accurate positioning of objects; the grid size (the distance between grid/snap lines) can be adjusted with the Grid menu or with the 1 to 9 keys. All objects will snap to the grid spacing; if an object is halfway between two grid lines, it will not snap to the grid lines. Instead, it will move one full grid unit at a time, always staying halfway between two grid lines.
The grid is used in both the 2D and the 3D view.
The 2D view is located in the left half of the window by default. It shows an orthographic view of the map from either the top, the front, or the side. All map objects are shown as wireframe in the 2D view.
To pan, right-click and drag; the cursor will disappear and you can drag as far as you want without the mouse exiting the window. (The texture view also allows panning with right-click and drag.)
To cycle through the top/front/side views (which are also known as the YZ, ZX, and ZY views because of the "slice" of the map they show), press Ctrl-Tab ↹.
The camera view is a 3D viewport; its controls are similar to first-person shooter games. Unlike the 2D view, all brushes are fully textured, although shaders are not used. The camera view can be controlled with either the mouse or keyboard shortcuts.
To lock the mouse cursor so that you can look around, right-click anywhere in the camera window. Right-click again to unlock the cursor. To move forwards and backwards, you can scroll up and down with your scroll wheel. Note that the mouse doesn't need to be locked to move forwards and backwards with the scroll wheel.
There are three axes along which the camera view can be manipulated; left-right, up-down, and forwards-back. To strafe (move left-right), press , or .; to move up and down, press PageUp or PageDown; and to move back and forth, press Up arrow or Down arrow.
Additionally, you can tilt the view with keyboard shortcuts. To look up or down, press a or z; to look left or right, press Left arrow or Right arrow.
By default, NetRadiant's movement step distance is rather large; to slow it down, open the preferences window and adjust the Movement slider in the Settings>Camera view.