If you're not an Admin or a Billing Moderator:
You will need to contact your Workspace Admins and request an upgrade to the Workspace to access the file(s).
As the Admin or Billing Moderator:
From the Lumin home page, click on your profile icon located in the top right corner of the page.
Then, select Billing.
Click Our plans.
Select a plan, then click Purchase now.
Add your payment details.
Then, click Complete purchase.