As Chuck indicates, using a tabbed browser (such as Firefox, which is what most of the 'regulars' around here use) helps.
If I want to Google something, to answer a question here on AB, I start by going to File > New tab. (So that I've got AB open in one tab and Google in the other). When I find I site I want to link to, I right-click in the address bar and select 'Copy'. Then I return to the first tab, right-click in my post and select 'Paste'.
If you're not using a tabbed browser, you can do exactly the same thing by using two windows. Instead of going to 'New tab', click on the browser icon at the bottom left of your screen. You'll then have two copies of your browser running simultaneously. (Just click on the two boxes at the foot of your screen to toggle between the two).
If I've read your post correctly, you also want to know how to post a link like
this .
If you click that link, and look under 'Posting guidelines', you'll see how it's done.
Chris