1) Log into JustHost user appropriate username and password
2) click on 'cPanel' (up top)
3) scroll down to the 'Domain Management' section
4) click on 'Subdomains'
5) Enter name into field labeled 'subdomain'
6) Click on 'Create'
7) Return to cPanel by clicking on 'Home'
8) go to the 'WordPress' Icon
9) Select 'start' (which creates a new install)
10) click on 'install'
11) select the subdomain created in steps 5 & 6 above from the dropdown list
12) select show 'advanced options'
13 give the site a sitename or title
14) set admin user name and password as desired