Install the Plotalot Component using the Joomla Extension Manager in the usual way. If you have bought the paid version, also install the Plotalot Plugin.
In the admin interface, you will find a new component "Plotalot", where you can create and edit charts and tables. You will also now be able to create menu items of type “Plotalot, Simple List of Charts”. See Showing Charts Using a Menu Item for more details.
To install the Plotalot plugin, use the Joomla Extension Manager in the usual way. Check that it is enabled in the Joomla Plugin Manager. Then see Adding Charts to Articles - The Plotalot Plugin for more details.