Tilaa does not supply SSL certificates but these certificates can be obtained from different companies like Xolphin or Comodo. To request a SSL certificate you will need to generate a Certificate Signing Request (CSR) together with a private key.
Create a CSR:
Log in to DirectAdmin and change from admin to user level on the right side of your screen. Navigate to Advanced Features → SSL Certificates and tick "Create a Certificate Request" and enter all requested information:
When using a wildcard certificate the Common Name must be in *.yourdomain.com format. When all requested information has been filled out you can click save to generate the CSR. Use this CSR to request the certificate.
Installing the certificate:
Log in to DirectAdmin and change from admin to user level on the right side of your screen. Navigate to Advanced Features → SSL Certificates and tick the radio button "Paste a pre-generated certificate and key"
Open your Private Key file and your Certificate file in a text editor and paste them both in the text box. Begin with the Private Key followed by the certificate. When you are done, click Save:
Your certificate is now installed. Some certificates require a root and intermediate certificate to be installed also. Go back to the SSL Certificates page and click 'Click here to paste a Root CA Certificate" and paste the intermediate certificate followed by the root certificate in the text box.
All certificates are now installed.
Please make sure to login on the user level for the relevant domain you're trying to get a SSL certificate for. If you don't do this you will get a private key mismatch during the actual installation of your certificate unless you save the private key in a seperate file when you generate the CSR. (DirectAdmin won't save it for you when you are on the admin level).
For reference please see the following article regarding this matter: https://help.directadmin.com/item.php?id=371