Install the component the same way as other Joomla extensions: go to admin panel "Extensions"->"Extension manager", select installation file "com_ipricecalc_1_5_xx_J25-30.zip" and click "Upload & Install". You do not need to uninstall an old version of IPrice calculator before installing the new version. Updates will be done automatically.
If you used IPrice calculator LIGHT version 1.1.7 or higher on your site, then You DO NOT need to uninstall an old version before installing IPrice calculator.
If you used IPrice calculator LIGHT version lower than 1.1.7 , then You NEED to uninstall IPrice calculator LIGHT before installing IPrice calculator. In this case You need also to remove all IPrice tables from your database before installing IPrice calculator (all tables with prefix #_iprice_).
Install necessary modules and plugins after installation of the component.
Set component parameters after installing: "Components"->"IPrice calculator"->"Sections" - the tool button "Options". Parameters are described in chapter "Backend: component parameters". Then create menu item with type "IPrice calculator"-"Price list" or "IPrice calculator"-"Catalog". Then set the parameters of the component in the menu, if necessary. The menu parameters of the component overrides global component parameters if they are specified. Add sections, categories and items manually using Section, Category or Item manager or import items using CSV file. Define discounts using Discount manager and specify a discount for items.