Question:
value1 = highest(high,30);
How can I modify the above to find the highest high for bar range of 10 through 30 bars ago?

Answer:
First of all, note that in EasyLanguage Highest(High, 30) returns the highest High value of the referenced datastream, between the current bar and the 29th previous bar (i.e. between High[0] and High[29]). So, if you want to know the highest high between 10 bars ago and 30 bars ago, you could use an EasyLanguage statement like the following:
value1 = Highest(High,21)[10];
That returns the highest High between High[10] and High[30].

The following statement return the same value:
value1 = Highest(High[10],21);

Regards,
David O’Dell