How to deal with process that needed to be done in sequence

For example, The user need to create records for Person and Account first before making a record for Product.

All 3 of them were just displayed in a sidebar, but I think that would be confusing for the user.

That’s an interesting point.

Could you elaborate more the situation or link to an example to make the context clearer?

Well, I imagine what you’re describing is a checklist style screen, which is common in installers.

You could display the steps, but grey them out (make them appear ‘disabled’), and then ‘enable’ them one at a time as your user walks through the checklist.