you need to merge chapter2 into the previous chapter1 folder. if you are using pc, you just need to select all the files in the the chapter2 folder and drag them into the chapter1 folder and press on replace. if you are using mac you need to press on the option button while dragging and press on merge.
you can look in the Ergi installation guide.pdf that is available on this page, and if you still have problems its better to ask in the discord server (link is on this page too)