When you write your frame set, instead of hte body tag you will use a frameset tag. In it you will define your frames.

So first decide... rows or columns (later we can discuss how to use both)

<frameset cols="XX,XX" or rows="xx,XX">

these x's are the placeholders for the size of each frame. you can define them in either pixels or in percentages.

So you could write <frameset cols="100, 500" > which would give you a frame set with a left column of 100 pixels, and a right of 500 pixels. And might look like this (only bigger)

But wait! You don't know how big your viewers computer is! A better way would be to write it like this

<frameset cols="100, *" >

Now it will make the left column 100 pixels, and the right will use all the space left over.

You can also do it with percentages!

<frameset cols="25%, 75%" >

Of course, this should always add up to 100%. otherwise you may see some weird behavior in your browser...

Next