OK, I have have two arc’s side by side as per here and have been trying without success to make a face of the curved edged surface between the two. I cannot seem to find the answer on the internet (or I am asking the wrong question??) and trial and error is getting me nowhere - any ideas please?
If the arcs are equal, draw a chord, endpoint to endpoint on one arc, creating a face. Then push-pull this face towards the other arc to create (by extrusion) the curved surface between the two arcs.
In the end delete the two chords of both arcs (the one you drew and the one by extrusion).