AlexanderMac

So I've watched lots of tutorials on how to use the 'add' tool to combine two separate curves into one, but the result I'm getting is completely wrong. I've selected both the letter 'i' and 's' and they should join together where they overlap, but when I hit the 'add' button the second picture shows the actual result I'm getting. I've tried selecting them first with the 'move' tool and then tried with the 'node' tool, but each time I hit 'add' I get the same result.