Dekken means to cover but can also be used as "de tafel dekken" or to lay the table.
In order to help us remember this meaning it is useful to look to the etymology of the English equivalent "to deck".
deck (v.) "adorn" (as in deck the halls), early 15c., from M.Du. dekken "to cover," from the same P.Gmc. root as deck (n.). Meaning "to cover" is from 1510s in English. Replaced O.E. þeccan.