what should I study and learn first

I've be watch all of andrews how to play piano video (very good by the way)after I purchased a piano, but not sure exactly where to start on my quest, I saw he is now working on a theory set and I'm thinking I should work on music theory first, hope that will give me a jump start on learning how to play the piano, I tried playing and practicing after watching the how to vids but got quickly confused and frustrated mainly over the music sheets even the simple ones like amazing grace or christmas songs so any suggestions would be greatly appreciated

1st practise your finger to relax press the piano
2nd practise fingering in BEYER book and practise sight reading
i think that enough for beginner...iam now in BEYER no 66 o iam still learning too trom zero its about 1 year

You basically have problems with reading the sheet. You should then first consentrate on learning the names of each line on the sheet.

This exercise is actually very nice:
http://www.musictheory.net/exercises/note

And you need the circle of fifths, mainly to guide you in what scale the sheet is written in. Andrew has a video about that one I think. There's also some info about it on wikipedia.

I don't know how exactly you studied by Andrew's videos, but what I'm doing actually is writing down all the information he passes on his tutorials and I constantly read over them so I can comprehend the lessons better and in case I forget something I won't have to go back to the video, 'cause I have it all in paper. So a nice way to start off is practicing everything he's already shown, but I don't know if you'll have free will to watch them all over again.

BTW, that music theory link that Victor posted is pretty cool. You can start off there.

Happy practicing.