Hey!
We didn't done the GUI for configuration so you have to edit /etc/telescope.conf:
scrolling.enabled
background.filename
header.left.filename
header.right.filename
header.middle.filename
border.color
border.width
text.leftMargin
text.rightMargin
closeButton.xSpan
closeButton.ySpan
text.font.size
text.yOffset

That's all confs for now.
You will able to configure the decorator as soon as Telescope will not use the images to draw decorator.

By installing the theme i am creating. But its not ready to use right now.