The AppBuilder is a Visual Studio extension which can be downloaded from the regular Visual Studio Gallery or by searching for "Sitrion ONE" in the Extensions and Updates menu in Visual Studio. To install the AppBuilder, please make sure that the machine where you install the hub has the following prerequisites:
The AppBuilder requires a Visual Studio 2015 or 2017 (Community, Professional or Enterprise). The Express Editions are not supported, since they don't support extensions.
The AppBuilder is an extension to Visual Studio. Based on this, the hardware requirements for AppBuilder are the once which are used for Visual Studio.
The AppBuilder connects during certain actions (publishing new Cards or Micro-Apps, access to devcentral.sitrion.com) to the ONE Cloud environment. Therefore the AppBuilder requires a direct internet connection without a proxy.
If you create scenarios working with backend connectors, you may also need connectivity to the given backend system (e.g. SharePoint, SAP)