Crust- To get through the crust to get to the mantle you would need a drill to drill a hole to get to the mantle. you would need a lot of water, a light to see where your going. Mantle- To get through the mantle to get to the outer core you will need lots and lots of air to breath. Outer core- To get through the outer core to get to the inner core you need another drill because your other drill broke. Inner core- To get through the outer core, mantle, and the crust you would need some string to pull you out.
The middle is the inner core , the one before the inner core is the outer core, the one before the outer core is the mantle, and the one before the mantle is the crust. The order it goes in is Crust, Mantle, Outer core, and the Inner core.