A presentation will usually consist of some kind of speech or talk, and it will often have some kind of visual component. Scholarly conference papers might not need a slide show, especially in an informed environment. However, the audience often needs some help following along. Common visual aids are transparencies, electronic slide shows, and posters. Don't worry about learning to use PowerPoint.
Recent versions are extremely easy to use, and the learning curve is sharp and quick.
Posters are just like those posters from high school. It's odd the electronic age would still require construction paper, gold foil, and paste, but posters are extremely popular. They make good sense when the audience is ignorant of the topic, or the environment requires a big portable display. The following web sites help explain how to create oral presentations, as well as the visual aids and posters. This site contains several excellent and thorough tutorials about presentations, speeches, overheads, and posters.