How do you add refill leads to a bic e3 pen?

You can buy 0.5mm lead at any office supply store.

With tip of mechanical pencil pointing up, and bottom of pen resting

on something solid (table, desk etc.), push down on front of pen.

Remove any short lead pieces from pencil.

Drop new 0.5 mm lead into pencil.

Push lead all the way down.

Push down on barrel to extend lead as needed.