Open topic with navigation
The built-in mouse navigation mode is like an automobile. You set the mouse pointer to the middle of the render screen and then press and hold the LEFT mouse button. To move forward, ease the cursor upward - the farther up the faster you'll go. To move backward, ease the pointer downward - again adjust speed by the distance you move the pointer from the center of the screen. To steer, push the pointer to the left or right simultaneously with forward or backward motion. At first it may be a little difficult to move around, but with practice you'll get used to the control interface.
There are two other modes for navigation by mouse. Holding down the RIGHT mouse button instead can be used to translate the viewpoint directly sideways or up and down. Holding down both the LEFT and RIGHT mouse buttons simultaneously as you move the mouse up and down let's you pitch forward or backward. Holding down both the LEFT and RIGHT mouse buttons simultaneously as you move the mouse to the left or right let's you roll the viewpoint to either side (pitch is rotation about the local X axis; roll is rotation about the local Z axis).