It is same editable poly, How to connect this 2 parts into solid geometry
Apparently, you are looking for
Bridge command, which build a segment of pipe. Then you should switch to the
Border sublevel, select both borders and click
Bridge. Using this command’s setting allows to manage segments, twists and so on.
It also might be that you want to weld verticies together. In this case you have to place vertecies close enough to each other, select them and press
Weld. Choose appropriate
threshold value to ensure that only the verticies you need have been welded together.
By the way, it’s unclear what you’re doing because you are using orthographic projection. Press ‘P’ to use perspective.