midges and chronies can be fairly simple or very frustrating. it can be difficult to judge size and amounts of materials when just starting out. since midges are usually tied on 16 or smaller hooks, they can be hard to see and need to be rather exacting. if you are starting out on your very first fly having never tied anything before, with no lessons or anything of the sort, i would suggest starting out with something a little larger. perhaps a 10-14.
there are some good tutorials on this site. troutflies.com
this site has a beginners fly section, what to tie and how to do it. flyanglers
just my opinion, but if you are starting out. dont worry about what you are tying or for what reason, start with basic patterns and techniques that are universal to different patterns. practice one or 2 techniques on each hook and then move on to another set of techniques and so on until you have the basics. once you are comfortable and understand the whys, hows etc. move on to putting the techniques to use in a complete pattern. again, start out easy and at a comfortable size and then move.
but if you have your heart set on a size 20 bead head midge as your first fly, the link din provided is good.