Who's on First

A few Sundays ago  a young girl was bearing her testimony from the pulpit during fast and testimony meeting.

Young girl:  I'm so excited that next month I will get to be baptised by immersion.

Nate:  Who is Immersion?

Robyn:  Not Who but How?

Nate:  What?

Robyn:  Not What.  How.

Nate:  Huh?

Robyn:  I'll explain later.