Use an X-acto or other razor blade to cut out lots of lines. I can go into detail of which ones to cut or not to cut, but it's easier to see what you'll need in the next step.
Step 3: Fold!
See all the parts that are still attached? Carefully reach in and fold them in the correct directions.
Step 4: Glue!
For this step you will need a card that folds down to 6"x4" or you can cut one yourself out of card stock. With that in place, glue the cut out heart paper onto it. You may need to use the X-acto again to trim off any excess that goes over the edge.
Step 5: Give!
Now put the card in an envelope and give to someone you care about.
Pro tip: Life heart is even better when combined with other goodies, like chocolate, flowers, or a power tool.