OnTheButton is provided with comprehensive online documentation, available on your own OTB server. This is available for all OTB users within your establishment. Documentation is provided in PDF.
Genkior Systems provides a manual (PDF). This is revised once or twice per year and is available to ASA or ESA customers free of charge. A pdf reader is the best way to use the manual. The table of contents (TOC) and index each contain working hyperlinks, to aid navigation, allowing you to easily and rapidly search for and locate key terms.