The first step is to get them notarised by a Solicitor or Notary Public - they copy the document then stamp, sign and seal it to show they certify it as a true copy of the original.
The notarised document is then sent to the FCO (Foreign & Commonwealth Office) to apostillise it as legal and certified.
THEN I will take that document to Slovakia to be translated and sent to the Slovak government.
It's taken me a while to get my head around it but that's how I understand the process works at the moment.
Prices to get this done vary massively so I emailed a few solicitors asking for quotes before I got it done.
The solicitor I went to charged me £40 for the notary and I'm sorting the apostille myself; the FCO charge £30 plus postage but if I'd have asked the solicitor to post it off their handling fee was £57!
Other people I got quotes from charged £55 for the notary, £60 to verify the copy and £70 for the apostille so it is definitely worth searching online first.