To start cut along the cardboard tube and then mark it to the widths you want to each of your bracelets.
Then cut along the marked lines.
Now the fun part is decorating. Using the washi tape kids decorate them as you like.
You can wear the bracelets without the pipe cleaners, but for long term wear the pipe cleaners to keep them secured.
To add the pipe cleaners punch a hole at each end of the cardboard tube bracelet and then feed the pipe cleaner through it and twist to secure and do the same at the other end. These would make a great simple.