Leaflet zoom levels range from 0 to 28, with 0 being the furthest zoomed out. At a zoom of 0, the world is shown as a 256px by 256px image. Each increase in zoom level divides each 256x256 tile into four 256x256 tiles.
Most tile servers offer tiles up to zoom level 18. If you are adding a tile server, you may want to check its maximum native zoom and use that as the maximum zoom for the tour.
You will also see min and max zoom for the additional basemap images. In these cases, the values determine the range of zoom levels at which the basemap can be shown. That is, if you zoom out further than the minimum zoom of a given basemap, that basemap will disappear until you zoom back in.
As a matter of standards, all coordinates will be provided as [longitude, latitude]. This is how GeoJSON stores coordinates, since longitude corresponds to the x-value and latitude corresponds to the y-value (and x always comes before y in [x, y] pairs). Therefore, for consistency, the plugin will also use this convention wherever applicable.
The tile servers use the Mercator Projection, which maps the world into one flat plane. If your coordinates are in a different projection system, you will want to modify them accordingly.
All coordinates must be provided in decimal degrees. That is, longitude has a range from -180 to 180, and latitude has a range from -90 to 90 (note that actual range for most tile servers will be about -85 to 85).
The following examples use "x" for longitude and "y" for latitude. Some spaces have been added for clarity, though they are not necessary for the geoJSON.
[x,y] - a single pair with no nesting[[x,y], [x,y], [x,y]] - a set of points, has one level of nesting, must contain at least two points[[[x,y],[x,y],[x,y]], [[x,y],[x,y],[x,y]]] - a set of LineStrings, has two levels of nesting (first level of brackets enclose list of LineStrings, second level of brackets enclose list of points), must have at least one LineString[[[x,y],[x,y],[x,y],[x,y]], [[x,y],[x,y],[x,y],[x,y]]] - a set of LineStrings with additional restrictions, has two levels of nesting (same as MultiLineString), the first LineString references the main polygon, subsequent LineStrings reference holes within the polygon, each LineString must have at least four values and must start and end with the same point[[[[x,y],[x,y],[x,y],[x,y]],[[x,y],[x,y],[x,y],[x,y]]], [[[x,y],[x,y],[x,y],[x,y],[x,y]]]] - a set of polygons, has three levels of nesting (first level of brackets encloses a list of polygons), must have at least one polygon