You have probably been directed to this page because you need to install the trilithium.net root certificate. This procedure will configure your computer to trust the trilithium.net server certificates, which means you'll be able to communicate securely with our servers.
These ancient screenshots show the installation procedure for Internet Explorer 6.0 on Windows. The interface will look different on your machine, but the installation is usually straight-forward.
Download the certificate
First download the certificate in DER format or in PEM format. Either format should work, but some software requires one or the other. If you are asked whether you want to open or save the file, select Open. (Alternatively you can download the certificate and then install it by double-clicking the file.)
A window similar to the one on the right should appear. Select Install Certificate.
Install the certificate
The Certificate Import Wizard is shown. Click Next, ensure Automatically select the certificate store based on the type of certificate is selected, then click Next again and finally Finish.
A message box similar to the one on the right appears. Click Yes. If you have done this before you will need to press Yes twice - once for removing the old certificate, and once again to install the new one.
A final message box telling you that the certificate installation was successful should now be displayed.