Sorry if this has been asked but can some one explain in detail
how in detail combat works. While answering these questions
Specifically. Also sorry I am new

1 when you start a attack and you roll the right number where does
Your hit point go is it your choice and if so do you have to say my
Infantry attacks your tanks.

2 also if I have two countries (both german) can I attack attack another country
Using both countries and if so and I use infantry on one side do I have to on all sides
Basically do the attacking groups merge also let’s say if the one country attacks and takes over does the other attacking country go back to its original spot or does it go
To the country it attacks.

3 lastly if I use a plane and go 4 spaces and take over a country but I can’t move to land
Because I moved the max number of times already does it die?

By the way this is for the 1941 edition and sorry for bad Grammer and any confusing
Questions