1) Preceding 2) Preliminary 3) Preparative 4) Propaedeutic 
• (a.) Preparing the way for anything by previous measures of adaptation; antecedent and adapted to what follows; introductory; preparative; as, a preparatory school; a preparatory condition.
Pre·par'a·to·ry adjective [ Latin praeparatorius : confer French préparatoire .] Preparing the way for anything by previous measures of adaptation; antecedent and adapted to what follows; introductory; preparative; as, a preparatory school; a preparatory condition. 
[adj] - preceding and preparing for something
preparative adjective preceding and preparing for something; `preparatory steps`
serving or designed to prepare: preparatory arrangements. · preliminary; introductory: preparatory remarks. · of or pertaining to training that prepares for more advanced education.