Hoi 4 Noob

I have just recently got into the game from friends recommendations and I'm wondering if my experience is accurate or if I am misunderstanding things.

I picked Germany because I thought it would be strong and I could play a bit slow and just do basic missions trees and expand a bit.

Friends say don't go to war early so I do all econ tree until +1 research and then go into demand Austria with 1m troops fielded, they say no. Then I make demand on czek they say no. They are guaranteed by France.

My friend says just declare anyway you can beat Czek and France. I have maxed mountaineers lots of tanks and airplanes. I micro everything planes on front lines more troops on front lines... and every front line loses.

I have 4 groups of 24 2 on both front lines... then I set my navy to patrol and strike force but France navally lands anyway and I don't notice because speed 4 mp and they take all of north Germany in like a few days with trucks. And I'm constantly losing battles with more men even when I'm surrounding enemy troops they will win 1v3.

Feeling really dejected about the game. My friends said I should micro better but I really don't know what they mean. Or how to win these fights even with way more troops. This entrenchment mechanic and punishing overstacking are very confusing as a player of other paradox games.