Curently in my home I have 3 directories users,

user1
user2
marko

I am logged in as marko, when I do "cd marko" it puts me back to ~$ (and what is this ~$ anyway?)

Also when in this ~$ part i can do cd .drush and then I am in ~/.drush$ but don't get where that is. As when I am in ~$ and do "ls" command there is no .drush directory. Please help me clear this what is what?

~ means your home directory.
ls doesn't show files/dirs that start with . use ls -a to see all

I guess then ~ is home directory of my current logged in user?

Whate are dirs that start with . why do they have that dot and what does it mean?

Yes ~ is short for your home directory, you can do cd ~/some/path to get to /home/username/some/path

. files are hidden files/folders.

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