All you need to know is
jav-it.exe download /c cookies.txt /i "%Input%" /o %CD%
In the terminal, you first need to get the working directory to be the directory where all the stuff you downloaded is. When you first open CMD.exe or Terminal or PowerShell, it starts at C:\Users\yourUserName. You know where your stuff is but the terminal only sees the stuff inside C:\Users\yourUserName. You can call jav-it.exe from where you are but you need to specify the location. C:\where\javit\is\jav-it.exe. That's annoying so it is much easier to put everything in 1 folder and make that folder your working directory. Include jav-it.exe, and the cookies.txt. The other stuff is to catalog the videos and aren't really necessary but include them anyways. To change working directory use cd.
cd C:\where\javit\is
It should now show working directory has changed. Verify stuff is there with dir. Now you can call jav-it.exe without specifying where it is. "Input" is a string of the CID. Replace %Input% with the CID of the video you're interested in downloading. %CD% means current directory, so output will be the folder jav-it.exe is in. Of course you can specify a different location but be sure to put parentheses. "C:\where\javit\is\jav-it.exe". What you type in cmd.exe should be
jav-it.exe download /c cookies.txt /i "intdtb00518" /o %CD%
In Terminal or powershell it looks like
./jav-it.exe download /c cookies.txt /i "intdtb00518" /o .
To call script you can double click but the working directory is the folder the script is in. You can also type it out in the terminal. for CMD:
download.bat
for Terminal or powershell
./download.bat