How setting zéro z

See:

https://my.carbide3d.com/gswso/06/

and

https://my.carbide3d.com/gswso/09/

as well as:

https://my.carbide3d.com/gswso/10/

https://my.carbide3d.com/gswso/11/

https://my.carbide3d.com/gswso/12/

Setting the origin at top center manually is shown at: