Our Lady of Mt. Carmel presented the Brown Scapular to St. Simon Stock with the promise that whoever dies wearing the Brown Scapular would be saved from eternal fire.
One should be enrolled in the Brown Scapular Confraternity. It is a simple ceremony which can be performed by any priest. Learn More Here.
If you have ever been enrolled in the past, even as a child, no additional blessing is necessary to wear the scapular.