This is a really good question and important to get right
Put the box upside down and fold in opposite edges til you have a flat bottom to the box
Place your tape about 1/3 of the way up the side of the box and tape over the gap
Then tape down along both open edges on the side of the box bottom
TOP TIP: warm up your tape using your hands before using it as that makes it nice and sticky!
Now all open edges are covered, put a strip of tape all the way around the bottom of the box to make it really secure. This makes sure that even if one piece of tape comes loose another will hold the box in place – the last thing you want is your items falling out of the bottom of the box on moving day
Turn your box the right way up - it's now ready to be used to pack your items
Once you’ve packed your box seal the top – this usually just needs one piece of tape
Label the box on the top and then you’re all done!