As SSL certifcates are installed per domain/hostname if you would like to be able to access a number of subdomains using secure connection you will have to use Wildcard SSL. Wildcard SSL as derived from the name is configired for *.yourdomain.com meaning  for all subdomains you create for your account.

If you have purchased an Wildcard SSL you should open a new ticket to TMDhosting Technical  Support team so that we may configure your domain and setup your certificate.