When creating an rdsh farm, I didnt understand fully what Min/Max was really for.... and can I change sessions per server later?

when creating my RDSH farms, I didnt really understand what the Min Servers was for (i understand i think max) but not really minimum. can you explain that in more detail?

also, is it possible to adjust the maximum number of sessions per rds server after the farm has been created ? I didnt seem to be able to do so,

thanks again

jayesh