As far as the semantic actions, only the word “open”, “close”, “lower” and “raise” are available. This is a limitation on the Alexa side. Regarding the RangeController metadata parameter actionMappings, you can either set a semantic action to a specific value or a delta value increment, in parenthesis, from the current state.
Some of your questions are answers in the post below, especially if you are trying to trigger Rollershutter commands instead of just sending a value.
