All those capital letters and numbers are hard to remember. Let's change your password so that you have some chance of remembering it.
For this, you'll need to pop over to your Account page, top right of your Simple Inked account, and into the Manage Users section.
You want to Edit your Administrator user, and on the right side panel tick Change Password. Type your new password, then type it again below.
Enter your email address into the Email: section, so that in the event that you FORGET your password, you can click the Forgot Password link on the login page and your password will be emailed to you right away.
Save your new login details and you're done.
Of course, you're going to want to create new login details for your staff users. To do this, click the New option in this Manage Users section and fill in the details on the right. You can create as many users as you need.
Note: It is a good idea to issue each staff user their own login details. That way all transactions, appointment updates, appointment deletions etc are tracked per user.