Originally posted by HitoshiMisaki:

alright and on my starting island where do i find all the bosses at?

You'll either RNG across their alter or more likely RNG across a locator stone that once interacted with will mark the closest(?) appropriate alter on the map. It'll mark one of them at least.

I want to say the Elder locator stones have a chance to spawn in black forest dungeons or near the broken stone towers in the black forest.

Edit: The game gives you a freebee boss locator stone at the spawn shrine to mark the first boss on your map.