I think you'd learn all you need just by checking the tutorials - things like buttons and sprites are very easy to create and monitor.
Personally I would use a TYPE, which would then be used in an array - this would allow the system to hold more than 1 character at a time.
name as string
age as integer
ATT as integer
DEF as integer
HP as integer
DIM dude(32) as rpgdude
Now there would be an array called 'dude', and you can access the components of the type quite easily, like say you just want to roll some stats...
Just using RANDOM(start,finish) to give basic values, but of course you'd go further than that.
One benefit of using a TYPE'd array like this is you can hold several characters data at a time - those could be heroes in a party, or even opponents... like you could have enemy characters in there as well, and use it to calculate encounters and combat automatically.
Things like a characters inventory or gear could be stored in another array, maybe an array of items with a TYPE component for the character number that is currently holding it, which makes it easy to drop or give items to characters.
I would suggest just getting stuck in, but take your time and consider the end goal and the data you need to work with. There are a lot of examples that explain the finer points, and there is always help and advice here.