Moving to the lower half of the projector's remote, on the left side are a pair of buttons marked Page, which you can use to control your presentation, moving forward and back. For the projector to be able to control your presentation, when you hook up to your computer, you need to not only connect the computer output of the projector with the provided cable, but also plug the USB connector (which is part of the same cable) into your computer's USB port.
Moving to the right side, opposite the Page settings are a pair of buttons for volume up and down and a smaller button above them for audio mute.
To further strengthen the 3400MP's ability to run your computer, there is a center round button, which is actually a joystick for moving the computer's mouse. Below it, left and right are the equivalent of left and right mouse buttons.
That finally takes us to the last two rows of buttons, left to right, the Source select, Keystone Correction, and Video mode (presets - PC, Movie, Game, User, sRGB). On the last row, there is an auto adjust button for locking onto the computer signal for the cleanest image, and a Blank Screen button.
A few competent remote control, I used it extensively, even used the remote mousing, and found it worked very well overall, and fit well in my hand, where, for example I didn't have to shift my hand at all, to use all the presentation controls. Well done!