You can apply them as a ramp or step load steps (depends on your load versus time plot).

I don't get it; I would like to apply 5 kN at 0 mm then at 10 mm apply 50 kN. Do you have any guide?

You have to apply the first 5 KN as a load step number one then you can apply the second 50 KN as a second load step. Then you have to use the command of Lssolve from 1 to 2. You can get more information about that in Ansys help.