person917,
whilst lua is the easiest of the two main PSP languages, that does not make it easy. Programming is a difficult concept, and game-making is even harder.
If you find yourself struggling with things like character movement, logic is going to be a b***h. Instead, spend a little more time following tutorials and maybe join a small project, where you can do some of the arbitary code, ask to see their source code, get them to help you out.
If you just started, game making isnt where your at yet.
I know this isnt what you want to hear, but to be honest, its the truth. It hapens a lot, that people make 5-10 posts, asking how to do movement, bullets, logic, scoring, menus and maps, and so the community writes the game for them.

If however, by 'just started' you mean you have learnt it all but are just a bit inexpereinced, dive in!
A bit of a tip:
If a character moves right, their x position increases (x=x+speed, where speed = integer that indicates how many pixels to move per second.)
I can't remember the y axis actually in lua, in c++ its the 'wrong' way around, kinda like in the botton right of a graph with all 4 quadrants. Lua coders, does the y axis increase up the side, or decrease up the side of the screen?

remember while loops? IF not, go backand learn them, they are important. An infinate while loop to detect button input, which calls functions for each direction of movement.

Didnt understand any of that? You arent ready yet. Go do more tuts!
Didnt understand 1 or 2 bits? Ask me, Im here to help. Most likely it was because I was rambling.

If you feel your ready to work on a game, Im recruiting lua coders of all abilities for 'CTU OS,' so PM me, and Ill send you my email address so you can send me some of your work.

Best of luck!
Chris
Because the world needs game programmers