Sharepoint 2010 Masterpages

I am helping a client correct a masterpage issue. I have close to no experience with开发者_StackOverflow SP2010 so I may be missing something simple.

The site is referring to a custom master page special.master. How can I find this file and edit it?

The masterpage is saved in the database rather than on the hive, so you can't edit the file just using VS2010 without first retrieving it from the database(and then upload it again). OR, you can edit it from SP Designer, as moi_meme has described.

use Microsoft Sharepoint Designer 2010 and find it in the masterpage library

see this video How to create a Master Page in SharePoint 2010 Designer