In English, you can be either one or more persons. So you specify by "you all" that you are talking to a group. In German however, "euch" means plural only, so you don't need to explicitly address them all. (Talking to your king/queen, you would use "Euch" while addressing only one person, but that is extremely oldfashioned ;-)
Usually, I would say "ich brauche euch" instead of the other way round. In this situation, where you enter a room, seeing the guys who should help you right now, you may begin with "euch..."
In German words can be in different orders, just wait til you get to dative case. But you can still tell that it's "I need" because brauche belongs to ich. If it was "you all need" it would be "Euch brauchen" I think. And if it was you all need me it would be mich not ich.
Hannibal-Barkas does a nice job of summing this up especially with his last paragraph. It really is best understood at this level as "Ich brauche Euch" - "I need y'all" (note that "all" is built into euch. To emphasize the who you are talking to, it can be properly moved to the first of the sentence, BUT the verb always is in second place, so we end up with "Euch brauche ich" to basically mean "Hey y'all, I need (you)!"
This makes no sense , even if euch is only plural , Ich should be first for , I need you all . I missed this one , answering with You need me , leaving the all out was wrong but still , having Euch first in sentence seems to me should mean You all need me . why would Euch and Ich be reversed in sentence stucture in translation to english ? Thanks to anyone taking time to help my ignorance