Walk to the Zodiac Village but youll need to finish the Xu Dog and Chen Loong quests first (this unlocks the area because they're connected to the Tiger's storyline). Once you get the Ruyi Scroll from Chen Loong, you can challenge Yin Tiger which is actually pretty smart to do since he teaches you skills youll need later.

The fight itself is tough but manageable because he follows specific patterns that you can learn. When you start the fight watch out for his spinning combo, since thats usually how he opens and its a good chance to learn the timing. This is actually similar to how later bosses attack which is why this fight is so helpful. The most important thing to remember is never attack when hes in that deflection stance because it reduces damage and lets him counter you hard (maybe interesting: his counter damage scales with how many hits you tried).

The best strategy is watching for his big attacks, dodge through them and then get your hits in during his recovery frames. Getting the Ebon Flow spell from beating him is totally worth it since it helps in a lot of later fights and the armor pieces are pretty good too. If youre having trouble maybe come back later with better gear, but beating him really helps you understand the combat system better. Good to know: if you keep getting hit by his spin attack try transforming right as he starts it, since the transform has some nice dodge frames that might help you get the timing down.