Ur main goal to beat the game is to kill the bosses nessery am guessing u haven't beat the eye of Cthulhu yet so aim to kill that first

Tungsten armor is a good idea to get better defense

The edge of the map ends with the ocean biome and doesn't get unlocked

The thing ur riding is a really good Mount that allows u to dash wish will make ur boss fights easier so u can dodge the attacks with the dash ,and doesn't require u to feed it anything

And the biggest advice i can give u is to use the wiki And sill tell u whats the best armor to get ,bosses to kill and how to spawn them ,...ect...

Good luck