To open media stored locally on your system click media open file and navigate your local files or press control +o on the keyboard to open files stored locally on your machine. If you wish to open media from somewhere on the internet on media press open network stream or press control n. To pause playback of a file press the button that look like two verical lines. To resume playback press the right playback button. To toggle fullscreen press the button which has the four corners of the screen to make it fullscreen and the four screens to have it back into windowed mode.
On the bottom right of vlc there is a bar that gets wider for volume. Click farther to the right to increase volume within vlc. Or hover the cursor over this bar and use the mousewheel to control volume. The button that looks like a speaker next to this toggles mute in vlc.