WHAT IS A "LINK"?
Underlined text is called a "link". By clicking on underlined text (and some photos), you are taken to one of three places:
A different part of the same page you're on (usually lower down)
Another page within the same website
A page on someone else's website
GOING BACK TO THE PREVIOUS PAGE
After viewing the page the link took you to, if you want to go back to the previous page (the one with the link), try clicking your browser's BACK button located on the top left of the screen (the button that's always there regardless of what website you're at). As a convienience, very often the designer of the page you're viewing put a "BACK" button or underlined "Back..." text somewhere near the bottom of the page, which will bring you back to where you were before you clicked the link.
The link you clicked gave you a new window, and there'll be no BACK button or underlined "Back..." text near the bottom. You'll know this happened because you can't click on the browser's BACK button; if clicking the browser's BACK button does nothing, this means you're in a brand new window (like this one you're reading now). To "close" a new window, click the X box in the upper right-hand corner of the new window. (Caution: Sometimes a new window is smaller than the previous window, so be careful to click the X box of the window you want to close.)