It's usually pretty straightforward. Just open the Manga Reader App, search for the manga you want, and look for the download option. Sometimes it might be in the menu or next to the manga title.
There are indeed apps for manga reading. For example, MangaZone and Crunchyroll Manga provide access to various manga titles. However, the availability might depend on your region and device compatibility.
I'd suggest looking into apps like Crunchyroll Manga. They sometimes have Berserk. Also, keep an eye on Kindle. Sometimes manga publishers make their works available there too. Just search and hope for the best!
It's quite simple. Just download and install the Crunchyroll app, sign in or create an account. Then, look for the manga section and browse the available titles to start reading.