Ultra extremely easy... you just pick a piece, without roots, simply piece of the branch and stick it into the soil. No watering is needed. The speed of growth depends on the kind - on the picture, you can see: tiny pieces planted on 19th of August (L) and same plants today (R), which is after one month. Two of them almost tripled its size, rest starts to get wider by sprouting new branches. That is ootdoor.
On the windowsill, indoor, little leaf of that lovely plant fell on the soil.
By the way - I forgot its name, do you know it?