Mikveh Immersion Procedure
Because complete immersion requires relatively deep water, one generally walks down stairs into the mikveh. If a woman has difficulty with stairs, arrangements can be made to assist her.
Upon immersing in the mikveh, one recites the bracha (blessing) " asher kideshanu bemitzvotav vetzivanu al hatevilah Who has sanctified us with His commandments and commanded us on immersion." Many Sephardic women recite this bracha while wearing a robe, and then undress and immerse in the mikveh. This is in accordance with the general practice that a bracha should immediately precede the performance of a mitzvah. The prevalent Ashkenazic custom, however, is to immerse once, recite the bracha while standing in the mikveh with the water at least waist-high, and then immerse again. Although one may not normally recite a bracha while undressed, in this case the water is considered a sufficient covering. One should not look down into the water while reciting the blessing. Some women also cross their arms below the heart to separate the upper body from the lower body, and some cover their hair with a cloth.
A woman must immerse at least once after she recites the bracha. Some women have the custom to immerse additional times or to recite additional prayers.