Learn German: Wir machen jetzt Schluss. - We are calling it a day now.

It literally translates to "make end". In everyday German, it is the standard way to say you are finishing work, ending an activity, or calling it a day. It is also the common phrase used for breaking up with a romantic partner!

Why is the time word jetzt placed right after the verb?

In German, adverbs of time usually come as early as possible after the conjugated verb. Because the noun Schluss works together with the verb machen to form a single core idea, it gets pushed to the very end of the sentence.

Could I use a sequential adverb like schließlich here instead of jetzt?

Yes! If you are describing a series of tasks, you could say Wir machen schließlich Schluss (Finally, we are calling it a day). The noun Schluss pairs perfectly with words from this lesson like danach (after that) or zuletzt (lastly) to wrap up a sequence of events.

Why isn't there an article like einen before Schluss?

Schluss machen is a fixed expression. Just like in English you might say "to make peace" instead of "to make a peace", German drops the article here entirely.