sastavljati

1. to assemble; to put together
   Ceo vikend smo sastavljali nameštaj iz Ikee. — We spent the whole weekend assembling IKEA furniture.
2. (of a list, document) to compile; to draw up
   Upravo sastavljam spisak za kupovinu. — I'm just making a shopping list.
   Trener još sastavlja tim za novu sezonu. — The coach is still putting together the team for the new season.
3. (of a text) to compose; to write
   Satima je sastavljala pismo za posao. — She spent hours writing the cover letter.

The perfective is sastaviti.