Where should we enter our desired rows(conditions) of excel

Builder
1

in the PsychoPyManual there is a heading called: “selecting a subset of conditions”. Can anybody tell me where should these values be entered and if there is a demo or youtube video containing this topic?
In general, this part of the manual is not clear to me at all!

2

Try Selected Rows

3

Thanks, yes I found it. but it is written that we could enter for example these things in the “selected rows”:
0,2,5
random(4)*10
5:10
$myIndices
Now the question is when I enter the second one (random(4)*10) in the selected rows, it doesn’t work.
And about $myIndices, where should I create this variable? It should be a column in a separate xlsx file? or in the same excel file I used for all conditions?