Which version of AdiButtonAuras are you using (enter the exact version number here)?

AdiButtonAuras-2.2.0

How did you install the addon (twitch client/manually)?

twitch client

If using the twitch client, what type of release did you install (alpha/beta/release)?

Release

If you installed manually, where did you download the addon from?

N/A

Which type of installation did you choose (nolib/normal)?

N/A

If your report is about a missing or wrong spell provide the following information:

• Your class: Hunter
• Your spec: Marksmanship
• Name of the spell (and spell id if known): Sniper Shot
• Source of the spell (core ability/talent/pvp): Talent PvP
• Do you use a macro to cast the spell (post the macro if so): N/A

If you have an error report, copy it below: N/A

I just need to create a ruler to trigger flash of the spell when enemy is below 20% HP

Please

Why nobody responds? What should I do to help me with what I need? Donate? Answer me, thanks @Adirelle @ckaotik @Rainrider

I don't have an active subscription so can't look up the spell ids for you but this was an old rule for warriors' Execute:

Configure {
	"Execute",
	format(L["%s when %s is below %s%% health."], DescribeHighlight("hint"), DescribeAllTokens("enemy"), 20),
	{ 5308, 163201 }, -- Execute
	"enemy",
	{ "UNIT_HEALTH", "UNIT_MAXHEALTH" },
	function(units, model)
		local foe = units.enemy
		local maxHealth = UnitHealthMax(foe)
		if maxHealth <= 0 then return end
		if UnitHealth(foe) / maxHealth <= 0.20 then
			model.hint = true
		end
	end,
}

And here is the general description of the Configure rule.