Using the Debug feature

[PhilOfPerth]

I wasn't aware of the betatest% option, @Pete, but it sounds like what I do at the moment: when I find an unwanted result from my programme, I add a line at that point like "locate 22,1:print "A% is": a%;"b$ is ";b$ : sleep 2 which shows what those variables are at that point. I was hoping Debug would sort of allow this in a simpler way. The only useful part of Debug to me at present is the list of all variables that it provides.
@mdijkens I tried the f8 and f7 and f4 options, but couldn't get any meaningful results - the screen blanked, and then it seemed to be waiting for something, I don't know what!