https://www.youtube.com/watch?v=oR5VPr8kGYY
Confirmed episodes as of now (according to the trailer)
https://mangadex.org/chapter/817cad27-2f0d-42e9-91d0-b6ef43d7e341
https://mangadex.org/chapter/853fa515-ada9-4e83-8bb9-a2fb36813ae3
episode 3 + 4: Summer in Ooarai! + More Summer in Ooarai!
https://mangadex.org/chapter/df4b79c2-97c9-40ad-8911-bdd3a36fa166
Episode 16: It's the Conditions in Anzio!
https://mangadex.org/chapter/934af4df-686c-496a-955c-8b468a4d91c9/4
Episode 33: The Rivals are a Treasure!
https://mangadex.org/chapter/19a58bd4-0d37-4e62-a6bc-16d62b4f7ad5
Omake 11 - Mini Pekoe

Four regular episodes+one Omake confirmed.

>>280423732
Act 1: 12/26 (Fri) ~
Act 2: 1/30 (Fri) ~
Act 3: 3/6 (Fri) ~
Act 4: 4/10 (Fri) ~

https://gup-mottolovelove.jp/post-220/