I recently had the exact same issue. Even using a few different websites to 'break' the pdf into text and then using Google translate, it did not tell me how to make payment which apparently is difficult to do. They give a long account number which is for their treasury account, but that alone is not helpful. Realistically, the only way to make payment is to find someone or an organization or perhaps a bank in Europe (with US branches maybe) who can contact the archives and make the payment. For example, Santander Bank is a foreign bank (Spain), or some USA based banks might have foreign branches that could assist. Then you can pay that intermediary either before or afterward. In my case I had an ongoing genealogy project with another organization in the UK which was able to make the payment on my behalf. I received a summary of the information I requested and a translation but am still waiting for copies of the actual documents. I paid about $20.