I would install Obtainium or Zap.store and install Amber, Citrine and Pokey through there. Here's direct links though: Amber:

GitHub

Releases · greenart7c3/Amber

Contribute to greenart7c3/Amber development by creating an account on GitHub.

Citrine:

GitHub

Releases · greenart7c3/Citrine

A Nostr relay in your phone. Contribute to greenart7c3/Citrine development by creating an account on GitHub.

Pokey:

GitHub

Releases · KoalaSat/pokey

Nostr "Pull Notifications" on Android. Contribute to KoalaSat/pokey development by creating an account on GitHub.

Here's a brief note I wrote about using Citrine