hit the button 5 times fast, PU is power up for adjusting the voltage up, PD is power down for turning it down, PO is for turning the unit on or off, CB is battery volts, AO is atomizer ohms, LO is led under the fire button on or off.
check your atty ohms, and adjust the voltage to about 2 volts higher than the ohms of the atty, thats a good ballpark to start.
the ext cap to use 18650s is worth every penny. i vape almost 2 tanks a day and only have to change batteries every other day. panasonic CGR18650CH's work wonderfully (but theyre flat tops, and need a magnet, or a bead of solder)