To use the Edit tool, first select the Edit tool from the Tools panel.
You can hover over an edge and drag to move it. Below is an example of moving a straight edge.
Here is an example showing moving a curved edge.
To move a node, hover the cursor over the node you want to move and the cursor should show a directional arrow. Then click and drag to move the node.
To edit a curve, you can drag the curve handles to adjust the curve shape.
To delete nodes, you can select them and then hit the delete key
These little bits help immensely.