Yeah Dryer knows...
You just hold it in your hands to warm the tank and some fuel comes up which you then light. The heat from burning warms the brass valve assemblt and passes he heat into the tank which drives the fuel up into the burner.

Don't knock it till ya try it.
Jim
P.S. some people made little aftermarket pumps for those who felt the need, but the stoves then overpressurise and don't work as well.