How can I effectiv select nodes, elements, faces in a mesh for groups

Hello,

often I import *.unv mesh in salome. Today I define the groups in mesh in a other FEM Preprozessor, because I have problems by define in salome. I don't understand, how can I use the filters in salome by group define...

First question's

# how can I select all nodes, elements, faces of a mesh?

# how can I select for example all nodes an a curve, a surface (by geometrie import in salome)?

# how can I edit the list of.. in salome? Can I edit in a etern editor how gedit and import this list?

Thanks an greeting

Markus