Where to start

Hello I am new to unreal engine 4. I would love if any one could give me tips on my current idea.
My idea is this tower defense game but not just build on the side. I want to build units and send them “Not to control them just send”
Also building can get destroyed because you build them on the path.
“Almost like the Strategy demo game”

What I am basically asking is how or where could I learn the following

“Main Menu Creating”
-Start game/New Game
-Load game

-Top down look
-Click on a tile to blah blah
-Selecting a building/cube and a Hud pops up where you can train units
-spawning units

“Enemy ai”
-Enemy sends units "I know I can spawn them but I would like it to be random so it build when it cans-
-Build a building same like sending units
I was thinking of every time the enemy receives resource it gets slipt in half like 50 goes to unit building 50 goes to building

"making levels and achievements "
–Check if the game has been won and if won it saves and pops up a menu where you can click continue witch loads another map up

Also can this all be done in blue prints?

Note this game is for PC maybe phone if it turns out ok but this is like my starter project
any help does help :slight_smile: