Help with custom AoE spells

How exactly could i make an AoE spell that casts something like mass sleep? So far I've started by basing the dummy spell off of Flamestrike. So what triggers would I use in order to detect the unit is in the AoE, and then create the dummy unit next to the targeted units and have them cast sleep?

Pick all units in XRange of Targeted point of ability being cast and add to unit group

Set IntergerVarible to Number of units in unit group

For each Interger 1 to IntergerVarible
Set UnitVarible to Random unit from unit group
Remove unit from unit group
Create 1 DummyUnitWithEntangleAndFlying0ScalingValue at position of
Animation - Set animation speed to 1000%
UnitVarible
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call UnitAddAbilityBJ( 'Aloc', GetLastCreatedUnit() )
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all IssueTargetOrderBJ( GetLastCreatedUnit(), "sleep", udg_UnitVarible )
Set UnitVaribleArray[For Each Interger) as last created unit

Wait .01

For each interger 1 to IntergerVarible
Unit - Remove UnitVaribleArray[For Each interger]
Unit Group - clear