In the current version you must a separate online tool, Wototo, to create your cache, identifying and describing the specific files and applications that it contains. Wototo exports a zip file that you download to your device, containing the descriptions and files for distribution. It is not currently possible to share other files or web apps on your device (please consider using a standard file sharing application if this is what you want to do).
This is an open source project - full source code is available on github, https://github.com/cgreenhalgh/opensharingtoolkit-kiosk/ (this is the chooser app).
This app is part of the OpenSharingToolkit, and has been developed with support from the Research Councils UK [grant numbers EP/J000604/2, EP/G065802/1] and the Horizon Digital Economy Research Hub.