This is a static page in RODA, in particular, AboutHelp.html.
In order to modify the contents of this file, one just need to edit file [RODA_HOME]/webapps/roda-wui.war/AboutHelp.html
Also, if one wants to have this page in multiple languages, one just needs to create one file per language. For example, to have english support create a file called AboutHelp_en.html, for portuguese (from Portugal) create a file called AboutHelp_pt_PT.html