Hi, Josh. Welcome aboard!
Were you wanting to get started on a BASIC game or something written in machine code? If the former and you're completely new to the platform, you probably want to start reading the original BBC Micro User Guide which is linked from the Useful Docs page of the wiki. If you're more a dead-tree manual person, you can pick up a copy on eBay pretty cheaply, including modern updates of the manual which include details of the latest modern hardware extensions.
The original User Guide will get you started with BASIC and also touches on how to embed assembler language into your BASIC programs. You can easily get started with that and a copy of BeebEm, the popular BBC Micro emulator.
If you're comfortable with writing assembler already, though, rather than writing it direct into BBC BASIC, you might prefer to use a modern 6502 compiler (like BeebASM or Ophis), with SWIFT - SteveO's Windows IDE for BBC micro development. Neil B has put together a shell project called Sparse Invaders based around SWIFT and P65 for creating a beeb game. You could start by getting that to compile and making some modifications to it ...
Once you've got started, feel to drop back here and ask questions in the Programming Discussion forum - everyone's usually very helpful and even patient enough to put up with my basic questions ...
Sam.
As Sam says, just post any questions and you'll get helpful responses. No ego's on here, won't be flamed or told about something being asked before, so post any question even if you think it might be silly