[SOLVED] Pop-up Page and Header template customization

I have been reading and searching for how to make my button Popup my window for my online store that is attached to the Template9 that i got from this site. I looked into the Absolute URL but that is as far as i can go with the template as any other javascript i try to use to pop out the page it just doesn't work. So, how would i create a button link that will pop out my Online store instead of opening another page and leaving the site?

In addition, I had customized the headers but the it doesn't seem to change. I followed everything to the T on your How to Edit this Template tutorial but it seems i am doing something wrong or something. I checked the custom.xml file and all my edits are right? This also happens with my Gallery too! I am not sure how to update these .xml files but i thought once changes are made all you have to do is save? Please help my website is www.cameroonpikin.com. Files are all in the appropriate places in the server! how do i customize these .xml files?