"The children went behind the building."
Translation:qach 'em lujaH puqpu'.
Basically. Verbs of motion tend to take their destination as their object (so no particular suffix, though it can be marked with -'e' for a little extra focus or emphasis) and the location of the motion (either the broad region in which the motion happens or the vessel which is actually doing the moving) tends to be marked with -Daq. You can also mark the origination with -vo'. However, just to be complete, it is grammatically acceptable to mark the destination/object of a verb of motion with -Daq if there is no location noted, but it is redundant and somewhat unusual. I have now added variations with -Daq as accepted answers.
Some words contain an inherent locative meaning. jaH go takes an object that is the destination of the going. That object is inherently locative. You can say vaS'a' vIjaH I go to the Great Hall and you don't need a -Daq because whatever the object of jaH is will be locative anyway.
If you added a -Daq anyway, it would be redundant, like saying vaS'a'Daq vIjaH I go to to the Great Hall.
Lots of other words have these "inherently locative" meanings, and many of them involve motion, so they often get called "verbs of motion."
But you could also say DujDaq vaS'a' vIjaH "I go to the Great Hall in a ship." or Qo'noSDaq vaS'a' vIjaH "I go to the Great Hall on Qo'noS." Note that the last sentence is not saying "the Great Hall on Qo'noS" (rather than some other Great Hall) - that would be Qo'noS vaS'a' "Kronos' Great Hall" - it is saying that the going happens on Kronos.