Need help in meshing a simple plate

Hello Kees,

Thanks so much. I've recreated my geometry according to the Wiki explanation. But, I've run into a problem when trying to follow the group creation. The Wiki instructions are:

For Code Aster we have to define groups for boundary conditions and the shell elements coupled to Face1. For the boundary conditions we choose all four lines. We select the lines by clicking New Entity --> Group --> Create:

* keep default choices except:
* shape type: select line
* main shape: Face1
* name: Linexo, select line Lx0, add, apply and repeat
* name: Liney0, select line Ly0, add, apply
* name: Linex1, select line Lx1, add, apply
* name: Liney1, select line Ly1, add, apply and close.

However in my case I only want to select one line, not 4, since only one edge is fixed. I don't understand how to do this, because the "Add" button is grayed out when the "No restriction" selection is active. Only the "Select All" button is available. I don't want "all" I want to select one line.

The other selections available are "Geometrical Parts of the Second Shape" and "Only Sub-Shapes of the Second Shape". If I select these, the Add button becomes available. But I don't know what the "Second Shape" means. Isn't there only one shape, Face_1?

I'm going to try to post here a screen shot of what I see when I try to follow your group entry instructions.

Thanks for your help!