While you read the manual, you can also try and look at other computer programming languages! I don't know anything about SmileBASIC yet since I don't have it, but from looking at some of the code posted on here, I could actually understand it a little!
Having even the slightest background in another computer language may help!
public class ThisIsAJavaProgramExample{
public static void main(String[] args){
for(int i = 0; i <= 1000; i++){
System.out.println("Programming is fun if you set your mind to it.");
}
}
}
The fundamentals are in chapters 25-27 of the manual: PRINT, Variables, and Conditional statements. Practice and see what you can do with those, because everything else that you do builds on those ideas.
There's also an online instruction list: http://smilebasic.com/en/reference/ I'd hold off on the sections relating to graphics and reading the controller until you understand the fundamentals.
After learning the fundamentals Ed said, learn how to make functions! Functions are essential when programming in any language. It's like making your own toolset.
Everything said up top is awesome. Thought I would drop this playlist on youtube videos done by PetitProfessor3D
https://www.youtube.com/watch?v=NX6lh-zpXGU&list=PLYF-xVMVFJbHvGkYi854_DmRbQasypQ25