This is the size of your bed, if you have a 235x235mm bed, put 235 in X and 235 in Y.
This is how detailed you want your bedmesh to be, the total number of points would be calculated by multiplying X by Y. Probing speed is the speed you want to mesh at, this will obviously be limited by your printers capabilties.
Take the X and Y offset of your probe from your [scanner] section of your config, if you do not know this information, please use this tool designed by Esoterical