ok, it was late when I replied, and I had forgotten the question by the time I got around to posting. was on auto pilot.
probably won't be any better this time around, still working through first cup of coffee.
any way
It would take longer than anybody has to explain fusion to a 5 year old, but hopefully I can give you enough concepts and key words to get you closer.
this model imported as a bunch of unconnected surfaces. Not a problem, just how the import worked. surfaces are just that, surfaces. they have no thickness.
ultimately you want a sold. a solid has thickness/volume.
surfaces and solids are both referred to as "bodies" in fusion. They have different icons in the browser. you use different tools to work on them. (notice the different tool tabs at the top)
if the edges of surfaces line up, they can be "stitched" together (stitch is a surface tool). once stitched, fusion will think of those surfaces as a single "body"
if the stitched surfaces encloses a water tight volume, fusion will automatically convert it to a "solid" body.
I brain farted on the rounding of the corners thing. there are a few ways to approach this. in my screen cast I extruded a solid from the svg, and applied fillets of the appropriate size to each sharp corner (from a machining stand point, you would want the radius to be a little bigger than your tool radius to control the chip load when it hits the inside corners).
I then used the combine tool to subtract the solid letters from the handle.
hope this helps some.
https://knowledge.autodesk.com/community/screencast/93fbf34c-d0dc-4a4a-af02-e7fd1fc1e9b8
