The images above gives you a rough guide to do your vinyl layout and how many stickers you will need. You can have bigger spacing and use less stickers or place them closer together and then you will need more. This space is a 2,5 x 2,5 metre wall and we have used 40 clouds. So one pack of 50 is more than enough for one wall.
The other option you can do is make a square template, this one measures 20cm x 20cm and then use your guide to help you place each sticker the same distance apart and inline with each other.