You should have received a Welcome Message from Blendable email address info@blendable.ca inviting you to register your HSA online in your secure Member Centre. The email subject is "Welcome to your OSSTF District 19 TBU Health Spending Account!"
Click the Set your password button in the Welcome message
In your Welcome Message are some instructions that ask you to click on the Set Your Password button to get started.
Choose password
That Set Your Password button will take you to a secure web page entitled Activate Profile that will ask you to choose a password. Once you've done that, you'll be directed to a confirmation page with the title Account Activated that confirms you were successful choosing and saving a password and that you can now login to your Member Centre.
Login to Member Centre
On that Account Activated confirmation page you'll be asked to login to access your online Member Centre. There's a link directly on the login page or you can navigate directly to https://osstfd19.blendable.ca.
If you've setup your account but are having trouble, see Troubleshooting Login Issues.