If you want new episodes from a show to be automatically added to your queue it's pretty simple.
Just go to the podcast, tap the three '...' in the upper right corner then tap Settings. From there you can enable "Auto queue new episodes" and as new episodes from the podcast are published they'll be added to the bottom of your queue.
Go to the podcast. Tap the Settings icon (cog) in the upper right. Enable "Auto queue new episodes" and new episodes from that podcast will be automatically added to the bottom of your queue.