There is some help on http://snap.berkeley.edu (without the /run suffix)
Check out the Reference Manual, which is also a concise introduction to the IDE: http://snap.berkeley.edu/SnapManual.pdf
and some introductory tutorials on Youtube:
About "Build Your Own Block: http://www.youtube.com/watch?v=Bbl2fh3igQ4
And on how to add inputs to them: http://www.youtube.com/watch?v=hZC2tDVYWBo
Also, there are helpscreens in the context menu for each block
There is some help on http://snap.berkeley.edu (without the /run suffix)
Check out the Reference Manual, which is also a concise introduction to the IDE: http://snap.berkeley.edu/SnapManual.pdf
and some introductory tutorials on Youtube:
About "Build Your Own Block: http://www.youtube.com/watch?v=Bbl2fh3igQ4
And on how to add inputs to them: http://www.youtube.com/watch?v=hZC2tDVYWBo
Also, there are helpscreens in the context menu for each block