This could have been a temporary marketplace glitch.
Please try again from within your Jira Apps page.
If it doesn't work then you can try to use the option to request a trail through the marketplace app listing: https://marketplace.atlassian.com/apps/37456/the-scheduler?hosting=cloud&tab=overview
Just make sure, you are logged in with Atlassian ID, when you generate licence it should be also visible on page with your licenses: https://my.atlassian.com/product
You can do edit from the project admin screen under roles. Click on the "pencil" icon against the lead name to edit.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.