Most trade scripts use a “cron daemon” to periodically execute their cron.php module, which means you need to be familiar with at least basic “shell commands” to perform the installation.
TE3 uses in.php method instead - we call this method “pseudo-cron”. You don't need to know anything about cron or SSH access, which makes installation process more user-friendly.
TE3 cron.php module is triggered by in.php. It has to be executed once per minute. Each time incoming tracking script is called (each time a surfer accesses one of your pages), in.php checks if 1 minute has elapsed since “pseudo-cron” was last activated - if more then 1 minute passed, cron.php is started.
“Pseudo-cron” executes all time-related tasks such as stats recalculation, toplist creation, writting log files (server log, history log, and some other processes), mailing and so on.
The objective of “pseudo-cron” is to be triggerred once per minute. If your site doesn't have any traffic or receives very little traffic, your TE3 will not be affected - “pseudo-cron” will execute all its tasks retroactively with the first incoming Raw hit your site receives.