This is nearly the simplest conversion that can be done, and a good one to do for a beginner. As the model is made of plastic all you need is a knife and some glue - and the parts used to make the model.
I wanted to play skaven, and then I needed a lot of verminkin. Most of them armed with clubs as that is a very effective weapon that are very cheap. As I like the models to be visual reminding everyone as to what they are, I decided to buy a box of the old plastic skaven where each model is made in one piece. This skaven looks a bit different from the new skavens and would form one (or more) henchmen groups.
Using a sharp knife I removed the blade and handguard of the sword
Then I cut a club from some of the sprue that was around the model.
Finally I used some liquid cement to glue the club into place. Gluing plastic to plastic with liquid cement welds to parts together, so no need to pin this.