First project (Excel web add-in)

First project(s); I've searched the web before posting this question, but no joy. I also clicked the help questionmark on this wizard and it just takes me to an error page. Can anyone point me to a detailed description or comparison of what each of these can/can't do?

I do have some project ideas, if it helps you suggest which path I should take:

(1) An add-in that pulls data from a target sheet, manipulates it, and creates a highly customized chart (hopefully based on a built-in chart if they've fixed the bugs since I tried this project in VBA, but otherwise I'll need to also find/add a 3rd party chart)

(2) An add-in that offers a few more sparkline formats

EDIT: the sparklines would include a ribbon button or group of buttons; the chart one would probably need a more complex user interface (task panel or pop-ups) but would also likely be opened using a ribbon button.