You MUST be in EDIT MODE to use these tools
toggle in & out of edit mode
Extrude:Select Edge/Vert/Face. Press E. Move cursor to adjust length
Add Edge Loop: Press Ctrl+R. Hover mouse over area. Use scroll wheel to adjust loop number.
Click>Slide in position>Right-Click to snap to center
Bevel: Select one or more edges. Press Ctrl+B. Move cursor to adjust depth. Use scroll wheel to adjust smoothness.
Change selection Mode
Inset: Select face. Press I. Move cursor to adjust depth.
Knife Cut: Press K. Move cursor to desired area. Click, then move mouse to another edge to connect edges. Press Enter to finalize.