Globe Artichoke help

hi, ive grown globe artichoke for the 1st time this year, I read the section in the John Harrison book that i should cut down and mulch the crowns over winter, this may seem a stupid question as im quite unexperienced but do i just cut the whole plant down so its all at one level? if so how much do i leave poking out of the ground? Also about a month ago, tiny new shots started to spring out around the base, is it best to get rid of these?

I really want to get this right as i followed instructions so far and have 3 big plants that produced alot of small heads this year.

Any help much appreciated.

thanks