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Double-click an operation in the Process Definition window.
Add the desired steps and activities for the operation.
Double-click a step in the tree on the left side of the window.
Select the Visual Aid Tools - Step tab. (Notice that the tab name changes depending on what's selected in the Layers pane on the right side of the window.)
In the Layers pane, select the layer you want new visual aids for this step to be available for editing (Assembly, Operation, Step, or Activity). A blue highlight color indicates the selected layer.
In the following illustration, we selected Assembly in the Layers pane and assigned the BOM block to the Assembly (process) level.