You can sort the episodes on your podcast into Seasons as well as include Trailers and Bonus episodes for each Season. Here's how:
Access the Content Management System (CMS) and select the podcast
On the left side click on "Sort Episodes". You can categorize each episode with the options Trailer, Full and Bonus.
Click on "+ Add Season" and select the episodes you want to add to the Season. On the bottom of the page click on "Move" and select the desired Season.
You can also move episodes from one Season to another:
Please note that this sorting will only be applied to and visible in Apple Podcasts. Check out this Spreaker blog post for more information.