First thing you need to do is to cut some para-cord into length. I used about 2 meter and my finished project ended up being about 550mm long. If you use a bigger ball or want a longer chain you would probably need more para-cord.
Once the cord was cut, I used a lighter to melt the tips to prevent they from fraying. Once done I started with a monkey knot to enclose and hold the weight in the chain.
I am skipping a few step to avoid confusion I am ''Knot" going to show you how to make a monkey fist because you will probably end up hurting yourself. Instead I will just give you this link. http://www.animatedknots.com/monkeysfist/index.php
If you used the the link, step 19 & 20 would be replaced inserting the ball and to pull the monkey fist tight so that both end are still exposed.