Basically the walker is a frame which the user takes with them and uses for support when their strength, stamina and/or balance while walking has been impaired by some condition or injury.
A basic walker is just a metal frame which is in a "U" shape where the two arms of the "U" are at the sides of the user and the base of the "U" is across the front of the user. The handles for the user to grip are on the arms of the "U".
The using of a conventional walker involves simply stepping into the walker, moving the walker forward, stepping into the walker, moving it forward etc. Disadvantages of this procedure are maintaining balance while moving the walker, some users may not have the strength to lift the walker, changing direction while walking requires the user to turn the walker while lifting and moving it forward.