You need to obtain a Soundcloud API key. If a friend of yours has one, then borrow that. If not, request one here by selecting "Register a New App" from the right hand menu. When filling out the form, for the reason write something like "for a personal site". You should receive a key within a week.
Head to your profile and grab your username from the URL. Like this: https://soundcloud.com/YourUsernameHere
Once you've received your key, copy the Client ID and your username in to the form.
Note: Soundcloud gets numbers wrong a lot. You may notice that your downloaded likes/following count is less than what you see on your profile or vice versa. I've seen accounts with 50 likes, but when you actually count them there are 9. We're grabbing all the data we can so please don't be mad at me!