If you want to change your default password all you need is to get to webapp (links are below), log in with your existing email/password, proceed to the account section, and change the existing password for a new one. Here is detailed information on how you can do it:
1. Open web interface:
2. Click Sign In button at the top right corner of the page
3. Enter your email and password sent to you by support team
4. After loggin in click your name at the top right corner of the page to open menu
5. Click Account in the menu
6. Enter your new password in Password input
7. Repeat your new password in Confirm Password input
8. Enter your previous password (that you've used to login in here) in Current Password input and click Update button
Your password is changed! Now you can login using your new password.