If you want to import the podcasts manually at a given time, you can use the feature "Import Podcast Now".
It will run the task for every enabled podcast feed.
Already imported podcasts will be skipped.
You can stop the import anytime with the Stop button.
At the end of the execution, a final report will display the number of imported episodes.
With the free version of Podcast Importer Plugin, you van run a manual procedure 3 times per day.
With the Premium version, there is no limitation to the amount of episodes and manual imports that you can run.