//get the first group layer that has at least one table
var grp_layer = MapView.Active.Map.GetLayersAsFlattenedList()
.OfType<GroupLayer>().First(g => g.StandaloneTables.Count > 0);
var map = MapView.Active.Map;//assumes non-null
QueuedTask.Run(() =>
{
//move the first table to the bottom of the container
grp_layer.MoveStandaloneTable(grp_layer.StandaloneTables.First(), -1);
//move the last table in the map standalone tables to a group
//layer and place it at position 3. If 3 is invalid, the table
//will be placed at the bottom of the target container
//assumes the map has at least one standalone table...
var table = map.StandaloneTables.Last();
map.MoveStandaloneTable(table, grp_layer, 3);
//move a table from a group layer to the map standalone tables
//collection - assumes a table called 'Earthquakes' exists
var table2 = grp_layer.FindStandaloneTables("Earthquakes").First();
//move to the map container
map.MoveStandaloneTable(table2, 0);//will be placed at the top
});