How do you create Directory sturctures?

A book that i bought is saying to use mkdir and touch to create a directory called "Unix1b" within my home directory with the structure at the following

Code:

Unix1b
`-- Unix1
    |-- admin
    |-- street
    |   |-- annex
    |   |-- building1
    |   `-- parking
    |-- faculty
    |-- history.exe
    |-- markham
    |   |-- outline.doc
    |   |-- programming
    |   |   `-- systems.pdf
    |   `-- security
    |-- course
    |   |-- gen_ed
    |   `-- lib_arts
    |       |-- english.txt
    |       `-- match.doc
    `-- mall
        |-- cafeteria
        |-- library
        `-- security
            |-- annex
            |-- building
            `-- parking

i did "mkdir -p Unix1b/Unix1"
then i did" cd Unix1"
username@matrix:~/Unix1> mkdir street
username@matrix:~/Unix1> mkdir admin
username@matrix:~/Unix1> cd street
username@matrix:~/Unix1/street> touch annex
username@matrix:~/Unix1/street> touch building1
now here is my question, what should i do for the for the parking in street directory.... what does that " `-- parking " mean?

am i even doing this right?

why when i "tree Unix1b"
" `-- Unix1 " doesn't show up
instead " |-- Unix1 " shows up
the same thing with parking

okay guy never mind...i managed to fix it. but can any one please tell me what that green folder "history.exe" is?
is it a directory? why is it green?
when I use mkdir , it turns out blue
what can i do to turn it into green?

thanks in advance

All the "|--" stuff is just ASCII art for the picture, nothing more (I guess you figured that out).

Well the name suggests that it is executable.

To mark a file as executable, do
chmod u+x history.exe