You can also add or edit a frameset in the HTML Source Editor. When a page contains frames, tabs appear at the bottom of the HTML Source Editor, one for each frame in the frameset, one for the page Layout (the Body frame), and one for the frameset.
The names of frames are assigned by default when you choose a frame on the AutoFrames tab of the MasterBorder Properties palette. The frame names display as framename_pagename.html for all frames that must change from page to page and as framename_masterbordername for all frames that do not change.
The default names are Left Frame, Right Frame, Top Frame, and Bottom Frame, depending on which type of frame you selected. Additionally, there are two other tabs: Body Frame and Frameset Page. The Body Frame tab displays the code for the page Layout. The Frameset Page tab specifies information about the frameset such as the names and attributes for each frame in the frameset and META tags for the page.

To edit a frame:
Click the HTML Source tab in Page view.
Click the tab with the name of the frame you want to edit. See Editing the Page’s HTML.