To create a new connection, click the button near the top of the swarm Settings panel. By default, you start out with a bunch of dots in space, but we can connect them in various ways to drive meaning and create relationships between the points.
There's a few different options here:
in row order depends on how your CSV file is sorted. The points will just connect across in the order that your csv file is structured (row 1, row 2, row 3, etc).
when column values match is the default, and you have to specify a column for that, which can be any column, although it is usually a categorical one. It's going to connect all of the lines by points that have the same value (for example: country).
by comma separated row numbers is used to specify connections directly from the CSV file, in one of the columns enter integers followed by commas into the cell. Those integers will match the index of the row in the data.
to axis or to a map adds drop lines where it connects the dot with a vertical line down to either the bottom of a chart's axis or if you're mapping points, onto a map.
You can also change the Size and Color settings of the connection lines. By default, color of connections match the dot, but it can also be a fixed or gradient color. The line thickness can be altered here as well.