In most cases, you should keep the default setting. You have to agree to these terms to continue. This is a regular Windows installation, just follow the instructions on the screen: To start the installation process, double-click on the downloaded setup file. On the part of the email server to be archived, no components need to be installed though.
Depending on the environment, archiving strategy and usage, MailStore Server can be installed on an already existing server, too.
Whenever possible, MailStore Server should be installed on a dedicated machine.