How to customize the prostar template

I would like to 'left-align' the hole Community Builder menu block (I am using the Prostar template). See the attachment:



To find out where I have to change the corresponding code I clicked F12 in the browser ...and was playing around, but I was not successfull ....can anybody help me

regards

Should already be left aligned. My guess is there's some CSS adding a left margin to it. You'll have to right click and inspect element on it to review the DOM structure and CSS in your browsers developer console then just work your way up the DOM until you've found what element has the margin.