On my 70-200 zoom camera lens when I rotate the focus ring there?

is a "Macro" setting with 1:5, 1:8, etc. How does this work and/or how can I use this feature in taking photos?

So-called 'true' macro is 1:1, which is very close, sometimes referred to as 'life-size'. If you have 1:5, it is one-fifth life-size; if you have 1:8 you have one-eighth life-size,etc. Getting into macro mode is done differently on different zoom lenses. Try taking pictures of flowers; my motto is 'fill the frame'.

You use this for getting very close to your subject so as to make large pictures of small objects.

http://en.wikipedia.org/wiki/Macro_photo...

There will be a button or a catch or pin that needs to be pressed so that the macro opens up. As it opens up, you will be able to magnify objects that are very close to the lens.

Macro is for close-up shots. You may have a small button or switch to select the Macro mode.