In Inkscape, go to File > Open
Go to Layer > Add Layer. Name it "swoosh".
PEN TOOL: Select pen tool and trace the swoosh. Start at tip and make closed shape.
FILL/GRADIENT/STROKE: Demonstrate how to use this tool, including gradient and stroke, even if it's not applicable here.
Lock "swoosh" layer. Go to Layer > Add Layer. Name it "background". Go to Layer > Lower Layer.
FILL/GRADIENT/STROKE (shapes, etc.): Make a background for your swoosh.
Go to File > Save As. Type in: "yournameNIKE.svg". Click Save. Go to File > New > Default (new window - close or leave open - up to you)