A prenda is built around an iron cauldron or similar vessel, filled with a specific combination of earth, sticks, palo being Spanish for stick and the source of the tradition's name, and other consecrated components assembled during a substantial initiation rite rather than a quick assembly job.
Restricted to initiated priests, plainly
Constructing a prenda is restricted to an initiated priest of the tradition, a tata nganga or yayi nganga, and this is a genuine closed practice restriction rather than a matter of custom or preference, an uninitiated practitioner does not assemble one before receiving that standing regardless of how much they may know about the tradition from the outside.
Ongoing care, and what happens when a priest dies
A prenda is understood to house a spirit bound in service to the specific priest who made or inherited it, and it requires ongoing ritual feeding and maintenance from that priest rather than being a static object installed once and left alone, contact by uninitiated people is generally restricted for this reason. If the owning priest dies without a designated successor, tradition specifies handling, sometimes burial, sometimes transfer to another initiated priest, rather than the vessel being treated as ordinary abandoned property, and this entry states that fact rather than detailing the specific procedure involved.