First of all, enable 'Edit' mode and the 'Adding' mode by clicking the proper toggles.

Click on the screen to create a new node. Click a node and drag to a target node to create an edge (recall that these are functional graphs so a node must have exactly one outgoing edge). Self-loops can be created by clicking a node and pressing the R key on the keyboard.
You can add a random functional graph and/or a loop by entering the number of new nodes and clicking on the proper button. For example, having entered 5 in the input box, as in the figure below, then
the leftmost button generates a random functional graph with five nodes; rhe central button generates a loop of size five.
The rightmost button can be used only if the screen already contains some functional graph. Following our former example, it will generate five new nodes and it will randomly attach them to the pre-existent graphs on the main panel.

Enable the 'Edit' mode. In order to add more nodes or edges just read the previous section. In order to delete nodes or edges, enable the 'Delete' mode with the proper toggle and click on the edge or node to delete it.

Click the node or a relation to delete it. You can remove a self loop by selecting a node and pressing the key R (Ensure you are in the adding mode to avoid the removal of the node).

Enable the 'Move' mode with the proper toggle.

Click on the screen to move the whole graph. Drag a node to move it around. Scroll to zoom in/out the screen content.

Graphs created with the Drawer tool can be either stored locally (and/)or downloaded. To store a graph locally, just provaide a name in the proper textbox or choose the default name suggested. Then, click on the button.
Drawn graphs can be downloaded using the button. Currently, only two file formats are supported: adjacency matrix or LaTeX.

When clicking on 'Advanced option' on the left bar, a series of toggles and buttons appears. The first block (see below)

can be used to inform the system if we want to keep on updating node positions (left toggle) or to stop updates (right toggle). Stopping updates can be useful, for example, when a satisfying graph drawing has been reached and we want to download it.

The following group of toggles (pictured below)
can be used to toggle the gravity force in the force-based system that is used to draw the graphs.

The last button will toggle the following specific drawing mode: all cycles will be drawn a regular polygon in the center of the drawing zone and the coordinates of their nodes will stay fixed along the updates of the system.

However, all the options in this section do not affect the structure of the graph, so feel free to experiment with them!