what is a folder, I don't have any folders?

It is a tutorial, it describes principles. It requires some extension on the part of the reader, not unusual for such.

There is a typo above, here is the page Basic Attachment Tutorial

After it worked through, I can answer any queries.

It's all in the tutorial, no point in repeating here.

No LCS.....

That old chestnut!

Works if started at the rectangle...... OS: Manjaro Linux (XFCE/xfce) Word size of FreeCAD: 64-bit Version: 0.22.0dev.36807 (Git) AppImage Build type: Release Branch: main Hash: cc96f2718e139d670e08c4226bdea9955a102ed6 Python 3.11.8, Qt 5.15.13, Coin 4.0.2, Vtk 9.2.6, OCC 7.7.2 Locale: English/Unite...

Great choice of file name ! I haven't got many of them!

Use the offset function in the tool......

Agree, the button should be shaded/different colour dependent on state.

3D CAD requires a little thought, a bit more and there can be a post at the end also.

I leave that to the student.

Select the last feature in the tree, and in the properties set Refine flag to true.