how can i add a subdirectory

A subdirectory of what?

It is just a folder inside of another folder. (A directory is the actual name of a folder.)

I'm trying to be helpful here when I say that I do not believe you have the experience to be managing your own server.

No knowing how to create a subdirectory is like a cook not knowing how to boil water.

I hope I am wrong.

Try:

mkdir /the/path/to/where/you/want/it/<subdirectory>

<subdirectory> is the name of the subdirectory you want.

Before you use it, you need to make sure that the ownership and permissions are correct for your application:

• (ownership) chown -- https://www.howtogeek.com/437958/how-to-use-the-chown-command-on-linux/
• (permissions) chmod -- https://www.howtogeek.com/437958/how-to-use-the-chmod-command-on-linux/

Ownership and permissions (esp. permissions) are slightly different for directories than for files. The two links above point these out. Read carefully, Grasshopper!

-- sw

i forgot to say that i was talking about my website @acanton77