Surf web and find iOS application or games. Whenever you tap on a link that refers to a an IPA file, Nassab warns you, and make you able to download and install that file directly on your device.
Nassaab uses the technique that iOS itself uses to install applications and games from the app store. This means that there is no need for any third-party application to download files first. Instead, Nassabb gives installation files to operation system and iOS takes care of downloading and installing them by itself.
In addition to browser, you will find a tab to search in 25PP database. In this databse, you will find paid applications and games for free, no need for jailbreak!