You can change the composition of a flow in various ways. You can:
To change the object inside a node, select the node. Using the drop down menu you can select the new object. Note that only objects of the corresponding type are shown.
To change the endpoint of a connector from one node to another, select the exit node and drag the link icon onto the new target node.
You can add a waypoint to a connector by double-clicking on the edge (line). Removing waypoints from an edge is done by double clicking on it.
You can change the location of a node by dragging it to another spot on the canvas. The exit of a node can be relocated around the edges of the node by dragging it.
You can change the size of a node by hovering over the lower right corner. When the resize icon appears, dragging it will resize the node.
By dragging a square or holding the CTRL-button while selecting items (nodes, connectors, waypoints), it is possible to select multiple nodes in order remove the selection or move the selection.