CTC 10CS Issues

[Mack1970]

Good afternoon everybody.
I am a complete novice to the world of 3D printing and need some (A LOT!) help please!

I have recently purchase a used CTC 10CS printer which powers up fine.
Unfortunately it doesn't recognise any files on the sd card.
There is no handbook supplied and I cant get hold of the guy I bought it from. (He MAY be busy atm!)

So I was wondering if any of you nice guys could advise me which type of file the machine recognizes?

And if there is a file converter recommendation, to convert files?

Sorry if this is a silly question but I did search a lot before posting!!

Thanks, in advance for any help!