Installation (in English)

www.ads-software.com by its technical nature requires that.

however, if you do not want to have an individual web site name, and if you don’t want to individualize your site, there is the alternative to create a(nother) blog at WordPress.com – https://en.support.wordpress.com/

WordPress.com and www.ads-software.com are independant entities – https://en.support.wordpress.com/com-vs-org/

if you have good enough reasons to want to create a site based on www.ads-software.com, start by reading https://codex.www.ads-software.com/New_To_WordPress_-_Where_to_Start

So, in other words, I cannot access/ use any wordpress plug-ins or dowload wordpress unless I purchase my domain?

So, in other words, I cannot access/ use any wordpress plug-ins or dowload wordpress unless I purchase my domain?

right.