Creating a border with sleepers - help needed

[MattWR]

Hi

I'm currently renovating my garden and would like to put in a border separated from the lawn by garden sleepers.

I'm going to be laying the sleepers soon and I need to know the best way to secure them into the ground as they will be going into the ground with the 'skinny' side as the top/bottom.

Is it just a case of whacking them into the ground and securing them by surrounding the majority of the sleeper with soil?

Or do I need to buy some kind of stake for them so I can attach that to the sleeper and then drive that into the ground? If so, how do I attach that to the sleeper? And what do they look like / where can I get them from?

All help is appreciated!

Thanks

PS - these sleepers are of the small variety, about 1m long and about 10cmx20cm square