"Hand outs" are materials that someone uses for explaining something, or in other terms - presenting something. These are written facts about the subject that you are going to explain or present to an audience. Manuals of your gadgets such as cellphones and tablets are great examples of hand outs.

To “hand out” is to distribute or offer sth (merchandise, gifts, tracts, etc.) A “’handout” is: 1. Food, clothing, or money donated to a beggar or destitute person. 2. A folder or leaflet circulated free of charge 3. A prepared news or publicity release.

Hand outs are usually a printed packet of material that allows you and assists you to follow the presentation. It could either be a copy of the presentation you are about to see or the presentation with elaborate notes on it.