Are you asking how one actually uses a punch to cut a shape? There's a slot to slide your paper into, and then you squeeze the punch and it cuts the shape. It's obvious once you have one in your hand.
Or are you asking how to use the shape once it's been punched out? In which case:
These are from a circle punch, I used foam dimensional adhesive to raise them up off the card
Birthday card By Stick
For the journalling block here I printed my journalling on cardstock and used the Fiskars Notebook border punch on the side (then inked the edges).
Garlic Fries! By Stick