Welcome to the MW Community, szotkowski !
If you want exactly 7 days ago, you could use the ruler tool to count how many H1-bars ago that was.
My MW says there are 341 H1 candles between March 27 1500h and April 16 1500h. Your number might be different, because some brokers open sooner / later and close sooner / later than others.
You could then lookup when that bar started
Java:
static Long time_7_days_ago;
time_7_days_ago = new long(series.getStartTime(index-341);
and use this 'time_7_days_ago' to draw on a chart.
Or just get that bar's info, like this:
Java:
High_7D_ago = series.getHigh(index-341);
Check this page on what info you can request:
https://www.motivewave.com/sdk/javadoc/com/motivewave/platform/sdk/common/DataSeries.html
Use
Java:
debug("price 7 days ago was " + High_7D_ago);
to output to your Study log to check whether your values are correct.
EDIT: for finer granularity you could work with the "getStartTime" and substract 7 days worth of miliseconds (= 604800000) from that number. And subsequently get values from the corresponding 1 minute bar.