can’t get away from relative link – text widget

Hi,
I’m trying to add an external link to my twenty sixteen themed website.

I’m using the “text widget” in a menu.
Here is what I have written:

Full page map of Yellow Brick tracking

when you click the link it takes you to this bad URL…..
svlexington/https://my.yb.tl/svlexington

Thanks!

Sam Moore