"The man wants a coffee."
Translation:Ο άντρας θέλει ένα καφέ.
Actually, the indirect article ενα or μια is used much less in Greek than in English. So, whereas in Eng. we would say: "He is a teacher." In Gr. the normal would be: "Αυτός είναι δάσκαλος." You would use "ενα/μια" for emphasis.
(On the other hand, in Greek you use the definite article much more than you do in English. But that's for another time.)
I want = (Εγώ) θέλω
You want (singular) = (εσύ) θέλεις
He/she/it = αυτός/αυτή/αυτό θέλει
we want = (εμείς) θέλουμε
you want (plural) = (εσείς) θέλετε
they want = αυτοί/αυτές/αυτά θέλουν(ε).
For this type of verb the simple present endings are -ω, -εις, -ει, -ουμε, -ετε, -ουν(ε).