Cylinder(Cone) Design - some questions

[mercury]

OS: Manjaro Linux (XFCE/xfce)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24291 (Git)
Build type: Release
Branch: makepkg
Hash: 7b5e18a0759de778b74d3a5c17eba9cb815035ac
Python version: 3.9.6
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0

I have a cone(see blue cone picture) which is a cylinder running in the middle.

I have designed the cylinder with the correct dimensions(circumference, thickness), but I noticed that the bottom piece of the cone is less thicker than the top bit.

Basically, the bottom piece of the cylinder goes down from the internal side of the cylinder.

How do I reduce the thickness of the bottom portion of the cylinder? Maybe just 20mm

Q2:

The cone(see picture) has another shape attached to it at the bottom.

Do I design this piece separately and then put the 2 pieces together? cylinder + other shape

Is there a tutorial on how to join the 2 pieces?

[Shalmeneser]

You should work with PartDesign_Revolution.

[mercury]

You should work with PartDesign_Revolution.

Thanks! I will download your freecad file and see how you designed it. Much appreciated