Your uncle may not know THIS version of BASIC. Just as C and C++ are slightly different, and use keywords that are exclusive in those languages, then the same goes with BASIC and SmileBASIC.
Aye! That is kinda difficult to work through, huh? My best advice is to invest in some books on BASIC. Several can be found on Amazon with some effort, sometimes at cheap prices, too. It's how they did it in the old days, and much of it still works!