I do not know of any tutorial covering that in particular, but the whole process is rather straight forward:

Load Figure and Sword. With Sword selected, choose from menu "Object->Change Parent", navigate to the "Body" of the Figure. Now Sword is a child of Figure.

You can pose Figure and Sword in whatever way you like. To save the pose for Figure and Sword together, just save the pose normally. To save only Sword's pose, when saving the pose there should be some button, "Select Subset" you need to click to choose only the Sword-bodypart. To save only Figure's pose, you use "Select Subset" to save everything except the Sword bodypart.

To save Sword save it to the library as a prop at which point poser will ask if it should save as a smart-prop (because Sword is child of Figure), which you should confirm. That should give you what you need to stab your Vicky with a sword, basically.