Hi Robert,

re:
> How i can make edge loop, i need extrude only that half of that face.

Draw in a line across the face, select the face and run Edit > Trim. At the prompt to select cutting objects select the line and push Done or right click in a viewport. At the next prompt to select which pieces to discard press Done or right click in a viewport to leave all pieces behind.

That should trim the face into 2 faces, select the half you want and then run Construct > Extrude.

- Michael