Lookng for help...hope im in the right section

I can not figure out how to install pure-ftpd on my kali linux. Iv done my research, and what i find is that it is as simple as entering apt-get install pure-ftpd and then BOOM your all set minus a few setup commands. Well not for me i guess?

When i enter that command it comes back with:

root@kali:~# apt-get install pure-ftpd
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package pure-ftpd

so it looks like i have to install in manually, which any research i have done, is as of zero help, research has been taking me back 2 steps. I got this far by myself:

root@kali:~# ls
pure-ftpd-thr- usr

What i did was download pure-ftpd from the website, then i think was unzip after that.

No idea what to do next, or if im even on the right track? Any help would be GREAT!