You can easily check your pulse on the inside of your wrist, below your thumb. 1  Gently place 2 fingers of your other hand on this artery. 2  Do not use your thumb, because it has its own pulse that you may feel.  Count the beats for 30 seconds, and then double the result to get the number of beats per minute.
It's not, LMB is Left Mouse Button. Its function can usually be replicated by the enter key.
The Fn key is a form of meta-modifier key, in that it causes the operating system to see altered scancodes when other keys on the keyboard are pressed. This allows the keyboard to directly emulate a full-sized keyboard, so the operating system can use standard keymaps designed for a full-sized keyboard.