Embossing... two different types.... one uses metal "stencils" and a stylus. Place the paper under the stencil and run the stylus through the design. It will make raised impression on the paper. The other type of embossing uses rubber stamps, embossing powder and a heat gun. It creates a raised design, usually a bit sparkly and glitter (depending on the type of embossing powder you use). Both types of embossing are very easy.
Distressing involves manipulating the paper to look "used" or vintage or just plain "worn out". There are different types of ways to do this., ... crumpling the paper, sanding the paper, and/or inking the paper to look older. Again, they are all easy techniques to do, but definitely take some time to master (easy to over do or under do).
Stamping just involves rubber stamps. VERY easy, but some people are SO creative with their stamping.... I've seen some done on TV and these folks think of things that amaze me!
Have fun at the classes.... you will learn a lot!.......................P