How do you make an object a member of workspace?

You have to change the parent property of the part to workspace, either by dragging it from its previous location into the workspace or by using a code to change the parent value.

Example:

local brick1 = Instance.new("Part")
brick.Parent = workspace

--Alternatively, you can use the second parameter of the method Instance.new, which sets the parent property of the new part created

local brick2 = Instance.new("Part",workspace)

open the tab view click explore drag and drop what ever parts you need in the workspace category

OR

make a script with this code

script.Parent.Parent = game.Workspace

then insert that into the part you need in workspace, when the game starts the part will be moved to your workspace.

If you use Parent.Parent you're going to move ( for example ), the Lighting to Workspace.

Use: script.Parent for a "Part" and script.Parent.Parent for a "Part" inside a Model.