The usual method is to get everything ready, the plastic sheet lined up perfectly, get the first staple in, only to find that you are out of staples.
So, check that your stapler is loaded! If you have a belt with a pouch for the stapler, all the better. Do the ceiling first. Cut the roll straight
across, using the roll as the "straight edge" so that you have at least 20 - 30 cm extra at each end for overlap. It is important to keep the cuts square to the edge! You can either run the sheet parallel or perpendicular to the direction of joists. In your case it would be easier to run with the joists, across the room because it is a smaller piece to work with, by yourself and your stuff is stored at the other end.
Open up the folds. Start in the corner with the overlap hanging down both on the end and the side. Tack it with 2 or 3 staples. Move along the end keeping the consistent overlap hanging down. Go to the middle of the tacked end and proceed across the ceiling. Use the back of your hand to push out the plastic ahead of your stapling (the plastic will slide over your hand), keeping equal tension back to the two tacked corners to keep things square, until you reach the opposing wall. Move to the next joist from center and do the same thing, keeping tension between the tacked end and the perpendicular middle joist. And so on. Do not tack the sheet to the joist and top plate, as you will find that the plastic shrinks a little, making fitting the DW into the corner difficult. Ideally the next ceiling piece will overlap the first over a joist. When you start putting the walls up, push the ceiling overlap up into the corner with a little extra and place the wall piece over it and tack it. Continue along the top edge, letting the sheet hang straight down and again leave a little extra in the wall corner to allow for the shrinkage. Or better yet make each wall a separate piece with overlaps and just a couple of staples in the corner to hold the sheet up. If you are using channels on the walls the shrinkage wouldn't matter as the DW doesn't go tight into the corner... When done, tape all joints with Vapour Barrier tape; ours is red and called Tuck Tape. Most other types of tape won't due since the glue dries out and the seal will fail. Tape any holes that may have appeared from the gremlins.