Typically, tabs work as follows.
There should be a set of six to eight tabs, from which the user can select. Using more than eight tabs can significantly reduce usability, as the user is being asked to select a single item from too large of a domain set.
Ideally, the items under the tabs should be already known to the user or easy to categorize. The categorization of items should match the user’s conceptual model of the data being displayed.
The tabs should be presented to the user one at a time. While the tabs can be categories, they can also be points on a discrete scale, for example, the letters in an alphabetical index.
All of the tabs should be shown to the user, with the items for the current tab placed immediately underneath it. Tabs should be shown as tabular sheets. This relationship should be reinforced by showing the tabular sheets visually, i.e., connecting the items area to the current tab.
Tabs should be placed horizontally. Consequently, the number of tabs that fit in a layout is usually less than ten, unless an alphabetical index is used. The tab labels should also be shown horizontally.
There should always be a default tab that is the first one displayed.
The currently selected tab should be highlighted visually.
It should be easy for the user to switch between the tabs. Each tab should be reachable with one click.