en_tn_lite_do_not_use/act/19/33.md

Alexander

This is the name of a man. (See: rc://en/ta/man/jit/translate-names)

motioned with his hand

You can make explicit that Alexander was showing the crowd that he wanted them to be quiet. Alternate translation: "gestured to the crowd to be quiet" (See: rc://en/ta/man/jit/figs-explicit)

to give a defense

It is not clear whom or what Alexander wanted to defend. If your language requires this information, it might be best to use a general phrase like "to explain what was going on."