Skial

Tips and tricks could also work too.

Echoes has it's own world of characters and story, there's only one connection to any other Fire Emblem game there and it's a post-game boss that doesn't really spoil anything about another game.

Here's a tip, don't try to rush through anything or you'll get your ass handed to you.

Do I play Casual or Classic since I am new?

Classic is what I played when I first played Fire Emblem but if you don't want to lose units that die in chapters then play Casual

Ok thanks Chance for the help.

Play Conquest on Classic/Lunatic like I did and be suicidal