How do I connect several parts via Server Script? (Union) [SOLVED]

I want to connect several parts that are in a model via a server script. I thought I could use UnionAsync, but I do not understand how to do that. Help pls

[SOLVED]:

local Parts = script.Parent.Model:GetChildren()
local Part = script.Parent.Model.Part:UnionAsync(Parts)
Part.Parent = game.Workspace