PHP variable

I need to create something like this I already have the webpage made but I need to be able to change user names like the example below; Example – my username is jonmroz so one of my links would be: [login to view URL] I need to put this at the end of the link and be able to change the name after the = ****(?s1=username)*** Im using a wordpress site with optimizepress theme... is it possible to do ? I will pay for this job and then I need to see how to do it myself if you can show me where to place the code. I have found these but not sure how to put it in: <? echo $_GET['s1'] ?> <?php echo $_GET['id']; ?>