How to Build a Lever?

There are different kinds of levers that can be built depending on the purpose it will be used for. A seesaw is a lever. A wheelbarrow is also a lever. The simplest lever would that of the seesaw type. This would require a lever arm and a fulcrum. The lever arm could be a board, and the fulcrum could be any triangular shaped object strong enough for the board to use for whatever it is that needs lifting.