Tasks and their related Worksheets can be created in two ways. They can be set by an administrator and allocated to a user or they can be created on an ad-hoc basis. 

For a task to be created on an ad-hoc basis it first must be enabled to do so. If you are an administrator wondering how to do this see this article. 

If you have been allocated to a Task Group that has access to ad-hoc tasks you will see   towards the top right corner of your screen.

A window will open on the right so that you can select the relevant Worksheet, add a due date and allocate the recipient/approver of the completed Worksheet. 

Upon pressing save a new Task will be generated and the relevant Worksheet will be created for you to complete

The Task will auto-generate the file name of: Worksheet Title - (Initials):year:month:day:hour:minute