[R] can't understand "R"

[Erin L. Leisz]

hi.  i really need help using this program.  computer language is a foreign 
language to me, and thus, i cannot make heads nor tails of the user manuals 
from the website.  i need to locate step-by-step examples of simple 
problems such as "graph f(x)+g(x) and f(g(x)) for the domain 0<x<2" and 
"graph 2H(x), H(x)+1, H(x+1)"  i do know how to define the functions, but 
that's it.  is there any help you could provide me?  i would appreciate 
some help asap.  thank you very much
erin leisz