Say, "Hallo." This means "Hello." The ha in "Hallo" sounds like the ha in "A-ha!" The o in "Hallo" rhymes with "low."
Say, "Guten Tag." This means "Hello." The u in "Guten" rhymes with the oo in "moon." The a in "Tag" rhymes with the ha in "A-ha!" Pronounce the final g in "Tag" with a hard sound between a g and a k.
Say, "Guten Morgen." This means "Good morning." The u in "Guten" rhymes with the oo in "moon." The or in "Morgen" rhymes with the oor in "door."
Say, "Guten abend." This means "Good evening. The u in "Guten" rhymes with the oo in "moon." The a in "Abend" rhymes with the ha in "A-ha!"