1) You have to open wrp edit
2) load your map,
3) add some objects you want randomly placed,
3) click file > import, then save as it as MYMAP.txt or something like that,
4) then you open wrp buddy and click on map and then import.
5) Then click on open .wrp file and load your map, you will be given a list of all the objects on your island,
6 )highlight the ones you want randomly placed on your island and then on the right select what you want to have done.
7) then click on save. I would suggest saving it as a new .wrp so in case you mess up the island somehow by adding way to many objects or whatever, you will still have the island that you had before loading wrp buddy.
open the new .wrp with wrp edit and look at the things you have done.
sorry bout the bad tutorial :-\