How do I come back from viewing the message to index?

[Boris Sobolev <immunogene@xxxxxxxxx>]

Hi List,

I am new to it, very new. After some struggle , I have installed mutt, and made 
it to send and receive the messages, but
this is about it. My first , but not the last question  is how does one come 
back to the index of my mailboxes, after
one reads and works with other messages? I start mutt with -y flag and can see 
my three shiny folders. I want to go
back there to switch folders. How?