G28        ; home
G29 P1     ; start the automatic bed leveling
           ; wait for bed leveling to finish (should take about 5 minutes)
G29 S1     ; save the mesh information into slot 1
G29 S0     ; save in slot 0 as well as Cura use slot 0 per default
M500       ; save EEPROM
M851       ; print the current setting
M851 Z0    ; set offset to zero
G28        ; home again
G1 Z0      ; move the nozzle to height 0
           ; measure the distance between the nozzle and the bed with some feeler gauge
           ; or stack several piece of paper and measure the thickness
M851 Z-1.6 ; enter the measure distance, in this example, the head is 1.6mm above the printer bed
M500       ; store the new configuration
G28        ; home again
G1 Z0      ; move the nozzle to height 0 - Then mesure again, if it's not right yet, restart at step M851 Z-1.6 (increase the value to bring the head closer to the bed)