To convert an Idea into a Task, click the Tdea, causing it to expand. The settings button is now visible:
Here you will see the option "Convert To Task"
Click "Convert To Task" to open this window:
Here you can: set a due date/time, assign the task to a Project Member, and write in any additional information. Once you have finished, click "Save".
To see all benefits of upgrading your Project to Premium, click here.