Select the profile and give it a curve modifier. Try the various alignments to see which one is correct… you can switch anytime though. The important thing is to see that the profile has jumped to the beginning of the curve.
Okay can’t add any more images to the first one…!
Here’s the rest of it :
Make sure you click the last two buttons in the modifier that allows you to see the modifier and edit the cage in edit mode! Then E to extrude, and drag. You will see the shape extrude along the curve! Is that magic or what.
The extrusion follows the turns of the curve. You can edit the curve later - or step out of edit for the mesh, edit the curve and go back to extruding.
This is IMO a lot less complicated than trying to fit something to curve. You can edit the extruded mesh afterwards, in place with those two buttons pressed… although this can be little wild.
If any moderator wants to tidy this mess up in any way please feel free to do so, even up to deleting the whole messy thread! I have messaged the two question posters here with the link to the forum thread the original posts were in.