Procedure

Import the image file that you downloaded
1. Use the icon or the File→Import… menu
Select the image you just imported and open the Path→Trace Bitmap… menu
Adjust the threshold value until the preview looks the way you want and click the Apply button

The Brightness cutoff Detection mode is the best for most situations. Changing the Detection mode to Edge detection will give you an outline effect. You can try adjusting other parameters to see how they affect the result
If some of the details that you want don't come through with the Trace Bitmap tool then you can manually trace them using the Pen tool

Don't worry about getting right on the details that you're tracing at first. After you have traced close all the way around the detail, zoom in and fine tune the path to line up with the image. Holding the shift key while clicking on a point allows you to create a curve handle
Delete the image that you imported
Use the Node tool to edit the vector and remove any items that you don't want

It's a good idea to select the Path→Simplify menu, but if it removes detail that you want to keep then just undo it.
Scale the vector to fit where you want it on the design and change the colors to match the laser settings you want

"Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect. - Romans 12:2"