Why is it so difficult to update, add/or change the planned velocity for an iteartion(s)? Every new quarter I see the iterations listed for that quarter with the warning icon next to them.

I then lick on every single menu item in the Plan and Track nav menus trying to figure out where the **** I need to go to change it. I eventually find it, but it's a huge waste of my time (I should create a feakin story for it since it takes me so much time, if I ever figure out my velocity searching for this has already impacted it!!).
I try clicking on the warning icon (that seems like it would make sense don't you think), but it does nothing. Yes, it's true in the past I've been able to figure it out, but as of now I haven't been able to for this quarter so far... and why should I have to waste so much time looking anyway? Short term memory is a *****, it needs to be accounted for on features that are rarely utilized, but do come into play eveyr so often. I should have to relearn how to do it every time it comes up.
A) Please make this easier in the future
B) Where the F do I go to update/change it?!