scan where i have 2 days of high volume in last 3 days

Well, one way would be to write a series of "or" statements where volume is large on two of the days and not on the remaining day -

so

and

day 1 is large
and day 2 is large
and day 3 is less than large

or

day 1 is large
and day 3 is large
and day 2 is less than large

or

day 2 is large
and day 3 is large
and day 1 is less than large


If you mean by high volume, "greater than the moving average x 2), then the first one would be

[ volume > sma(60, volume) * 2]
and [ 1 day ago volume > 1 day ago sma(60, volume) * 2]
and [ 2 days go volume < 2 days ago sma(60, volume) * 2]

I'll let you work out the rest. Watch your parentheses.

Or if this is too complicated, re-think whether this is the best way to capture what you are looking for.