How to use singlespeed side of flipflop

complete novice question - have looked at sheldon's site and here, but are there any basic guides about how to use the freewheel side of a flip/flop? i want to change from fixed to free but not done it before. can I fit the same cog on the free side without a lockring? laughably dumb i know but cant figure it...
cheers if you can link me to somewhere that explains it?

No. you can't.

You need to buy and fit a freewheel on there.
The difference is in the threads. The fixed side has 2 threads going opposite directions, for cog and lockring, and the freewheel side has a wider single thread for screwing a freewheel on.

if you want to ride freewheel, you need to buy a freewheel.

The only difference between the fixed and free side of the hub is that there's no threading for the lockring on the freewheel side. The ability to freewheel is inherent to the cog itself.

Go to a bike shop, and ask for a shimano freewheel, they're probably no more than £20. Then, take the back wheel off, grease up the threads of the free side of the hub, put a little grease onto the threads of the freehub (not too much mind), and screw it on!

Also as you pedal it will self tighten.
Helpfully.

This is the sort of thing you need:

http://www.sjscycles.co.uk/category-Freewheels--Single-Speed-76.htm

perfect - that 4-way response nails it thanks. almost co-ordinated by the gods.

thanks everyone...quin, asm, eyebrows, soweto....

i can get back to bad bike mechanics and being a depressed everton fan now

What you don't know, is that we're all the same person.

There are only 5 people on the forum, including you. We're all hippy. Not by choice, mind.