Drag a child task into a branch

Hello team, how can I order or drag the tasks vertically as the user wishes within a branch, for example I have the structure
father 1
–child 1
–child 2
–child 3
I want to order and I stayed like this:
father 1
–child 3
–child 1
–child 2

Hello,
You can use order_branch config of Gantt that activates the ‘branch’ mode that allows vertically reordering tasks within the same tree level:
https://docs.dhtmlx.com/gantt/api__gantt_order_branch_config.html ;
Please check the following example where you can reorder tasks in the grid:
https://docs.dhtmlx.com/gantt/samples/07_grid/02_branch_ordering.html