It's easier to add a HTML expression in EZPages, because their content is stored in the database and is parsed into the page AFTER the rest of the php compiles it. (There is a work-around, but its complex.)
In your EZPAGE editor screen, toggle to HTML (page code) mode, and put this at the bottom.
If you go a step further and encase it in a <DIV> with an ID, then you can style it in the stylesheet.
HTML Code:
<FORM>
<INPUT type="button" value="Click here to go back" onClick="history.back()">
</FORM>
HTML Code:
<div id="myBackButton">
<FORM>
<INPUT type="button" value="Click here to go back" onClick="history.back()">
</FORM>
</div>
history.go(-1) or history.go(1)
This allows you to determine how far forward or back to take the viewer. Use a minus sign and a number to go back, or just a number to go forward.