Learn How to Add a Node

Letter B starts with ellipse preset shape and requires 5 nodes

In previous step we created a new vector layer named B. On that layer draw a new ellipse preset shape.

Ellipse Tool
Colors: Black outline, fill color of your choice. I will use yellow.
Tool options: Ellipse, Show Nodes, Create on Vector, Line Style Solid, Width 3, Anti-Alias checked.

Edit the ellipse to create the shape of letter B.

Pen Tool-Edit Mode: Select ellipse, right click, convert to path.

The B is made very similar to the A, except for a couple of added steps. The ellipse preset shape has 4 symmetric nodes. Use the Pen tool to drag 2 of the existing nodes so they are positioned on the left side of the ellipse. These will become the top left and bottom left corners of the B. Then drag the 2 remaining nodes so they are on the right side of the ellipse. We end up with a mis-shapen rounded-corner box shape as shown above.

To shape a B however, we'll need 5 nodes, not 4. So next step is to add a node. We also need to change the Node Type so we have 3 asymmetric nodes and 2 symmetric.

Add a node between the 2 right-side nodes by holding down the Ctrl key and clicking the line segment when +ADD appears next to cursor. This new node should be asymmetric. Right click the node and select Node Type to verify. The current node type will be the one that is greyed out.

Change Node Type for the 2 nodes on the left.
Pen Tool-Edit Mode: Drag a selection around the 2 nodes, right click, select Node Type>Asymmetric.

Adjust the control arms for these left-side nodes to make fat, rounded corners at top-left and bottom-left.
Turn the control arms on the 2 right-side nodes so they are vertical and point up/down.
Turn and adjust the control arms to create the middle indentation in the B letter. This may take a little tweaking because, for this asymmetric node type, you can adjust the length of each control arm, but the not the direction. The shorter the control arm, the smaller the curve will be. Normally we would use a 'Cusp' node to create corner turns, but a 'Cusp' node will create a sharp angle instead of the rounded curve we're looking for. So just fiddle with it a bit until the shape looks similar to the B above.