All of the lower chime supports are identical.
When orienting the support on the bed, it is strongly recommended that you lie the support flat in the same orientation as in the final build. You might have thought that you could cram more parts onto the bed in one go by rotating the part so the arms stick up vertically. The problem with this idea is that the design depends on the supports being bendy enough to allow the arms to spread open when fitting the chimes to the supports. If the parts are printed with the arms vertically, then the layers in the print have a tendency to come apart when bending, and so the arms can snap off easily.
It is recommended that you add supports in your slicer. This helps to keep the ends of the pins rounded as designed, and so helps the chime to slide into place. If you don’t add supports, the chime support pins will have rougher ends, and so will need a bit of adjustment with a knife to make them fit into the holes in the chimes. This is not a big deal, and any roughness in these chime support point will be hidden inside the chime in the final build.
The default 20% infill works well.