How do i join lines together cleanly so they do not overlap

Do you mean when drawing onto the sheet? In this case you
can use the modifier keys (CTRL, SHIFT, ALT) to make the
drawing "lock" to cells. before you start drawing hold
down ALT and you will see that the line is forced to line
up exactly with cell borders - this makes it easier to
line things up.
-----Original Message-----
How do i join lines together cleanly so they do not
overlap
.