You can wear either hacking or show jacket with cream or white jods with long boots, skull cap, tie or stock and black gloves, white ones will just help the judge see if your hands move.
As for the tests I would contact the organiser who will point you in the right direction or may have copies already for those that enter.
Good Luck!
If they are using the British Dressage Intro tests they are available from the shop on the BD website. They usually arrive the next day. Some clubs make up their own walk and trot tests and will supply copies to you.