Would this work for a basis of an admin commands script?

1st pls can you format your code correctly by using tabs it makes it a lot easier to read where each end goes.

Currently your code will not work as you want it because this is a index value table

for _,v in pairs(adminlist) do -- if you wanted to do a index, value loop the format is for  [variable for index usualy i], [variable for value usualy v]
	if v == "3" then -- this will always run as you do not check the player userid so the first value in the table will allways be 3
	-- add commands for level 3 users
	
	elseif  v == "2" then
	-- add commands for level 2 users
	
	elseif  v == "1" then
	-- add commands for level 1 users
	elseif  plr ~= v then
		print("IsNotAdmin")
	end
end

You do no need to use the loops so lets fix this.

local adminlist = {
	-- so just to make 100% shure the [needs the user id] so we dont need loops
	[game.CreatorId] = {3},
	[NormalAdminId] = {2},
	[Moderator] = {1},
}

game.Players.PlayerAdded:connect(function(plr)
	
	local function levels(plr)
		if adminlist[plr.UserId] == 3 then
			-- level 3 cmds
		elseif adminlist[plr.UserId] == 2 then
			-- level 2 cmds
		elseif adminlist[plr.UserId] == 1 then
			-- level 1 cmds
		else
			-- this should never happern but o well
		end
	end
	
	if adminlist[plr.UserId] ~= nil then -- check that the user is in our list before adding things, nil is returned if not in list so this will not run
		levels(plr)
	end
end)