Hi alptekin1998, there are many different options to finish your model. One of them would be to use an editable poly tool in its border subobject: "Cap". After selecting the border of the open polygons, the cap will sealed it. After cup creation, you can turn the Snap tool ON (the main toolbar/Snap) - press "S" to activate it. Right click on the toggle button and choose the Vertex in the dialog. Now you can use the Cut tool from the editable poly tool-set to connect some vertices with edges. This way you will have more control for the shape you create.
