Draw the shape of the hole on the face you want it through - a circle, a
rectangle, anything closed.
Take the drill and click that shape.
It goes through whatever it crosses, however many walls that is.
The circle first, with the circle tool - the drill does not
make the shape, it takes one that is already there. Then the drill,
a click on the shape, and carry on down past the bottom of the box to go
clean through. The bar says how deep as you go.
Drill or push/pull?
Push/pull pushes a face back until it meets
something, and stops there. The drill does not stop - it cuts all the way
through and lines the tunnel on the way. For a duct through two walls, or a
bolt hole through a flange, this is the one.
Worth knowing
Where a new hole crosses one that is already there, both are opened into
each other, so a tee comes out as a tee rather than as two pipes that happen
to overlap.
Type a distance to stop it short of going through.
/holes afterwards draws any edge that nothing meets in red,
which is how you check the cut closed properly. See
solids and 3D printing.
See also
Push/pull - the one that stops when it meets something