Belenios supports a dedicated voter interface for Condorcet-Schulze, where voters give rank candidates by order of preference, possibly with equalities. You can find here more information on the contexts in which this method is well suited and how votes are counted.
Preparation of the election
On the page "Edit Questions", you need to tick the box in the insert that starts with "Alternative voting methods (warning, still experimental)" to activate this alternative mode. Click on "Prefill with Condorcet-Schulze" to prefill the field "Counting method specification".
By default, the voting interface will invite voters to rank the candidates, possibly with equalities. You may preview the booth ("Preview booth" on the main page of the preparation of the election). The rest should be self explanatory. ;-)