As said, there is nothing to 'convert' or 'deposit'.
For a confirmed booking, HGVC simply deducts the requisite points.
In the HGVC members' website, under the "My Club" menu item, there's a link to RCI Reservations which takes you across the bridge into RCI-land where you can search based on your criteria. The broader the criteria, the better.
You can, of course, call to make a booking, but the fee is higher. You can also call to request an 'ongoing search', if you cannot find something suitable. IME, the call center does its best to help (but you are paying for it, if you confirm).
When searching, you have access to both RCI-weeks and RCI-points (nights). You can use your points from the current year and the next two years. If you cancel a booking, you get the points back (subject to a penalty for late cancellations), but points from a prior year which would have otherwise expired, can only deposited (for a fee) into the RCI program for re-use.