Thank you for looking into translating OSM Scout Server. In Sailfish, only harbour-osmscout-server.ts version is used and it should contain all required strings.
To simplify translations, there is a project registered at https://www.transifex.com/rinigus/osm-scout-server . Please use it for working on translations of the strings within application.
Note that Valhalla routing instructions are translated as a part of Valhalla's project. Please see https://github.com/valhalla/valhalla/tree/master/locales for current translations and how to contribute.
User's Guide is located in docs subfolder of the project. For new
translations, fork the repository in github, add new language
subfolder by making a copy of docs/en, and translate HTML files into
your language. In addition, you would have to make screenshots on
Sailfish OS for the tutorials using translated application(s). These
screenshots would have to be named as they are in English version to
keep the same structure of the tutorial. Notice that tutorials
information text covers part of the screenshots. You would either have
to make screenshots which are very close to the English version or
start changing location of the information text to accommodate your
screenshots.
Some of the strings would contain macros in the form %macro%. These macros mark the positions in the phrase that would be filled in with corresponding data. For example, in string
Leave roundabout (%num% exit) into street %street%
keep %num% and %street% untranslated. These macros should be placed in the sentence where they are expected to be replaced by the exit number (%num%) and the street name %street%.
For road types, as requested in routing speed table, you may find it useful to see http://wiki.openstreetmap.org/wiki/Map_Features#Highway (link found by @eson57). Similar content in other languages: