You will kick yourself when you realise how easy it is.
There will either be a locking catch to keep the two together (if you cant't see it then there isn't one) or the locking mechanism will require a twist - similar to the lid on a glass jar.
You might also kick yourself for failing to say the make & model of your machine - I don't mind - it makes it more fun trying to help you solve your problem.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix vacuum cleaners.