How I got apt update and install to work (with Debian Jessie retired)

Good afternoon, dear participants!

Not expecting trouble, I installed larger hard drives on my ReadyNAS 102 with firmware 6.10.10. Before installing the hard drives, the Transmission applications (before the 6.10.10 update) and the Resilio synс were installed. In fact, I only need these apps.

After reading this forum, I followed all the steps from message No. 37 – updated apt and was able to install nano (I checked – a really convenient thing!). However, I don't understand how I can get Transmission and Resilio synс – on the "Available Applications" tab, I see only two applications: GLPI and PHPSysInfo for Readynas.

I'm not well versed in unix systems, so just by analogy with nano, I tried to install Transmission in this way.:

apt-get install transmission

And something has clearly been installed) However, after restarting the NAS, I do not see any traces of the presence of this program.

Question number 1 – if Transmission is installed correctly, how can I start it?

Also, after successfully checking the application installation mechanism through the "Install application" menu (using the plexmediaserver_1.41.3.9314-a0bfb8370_armel.deb distribution), I tried to find the Transmission and Resilio synс distributions for Debian 8 ("Jessie") on the world Wide web, but in vain.

Question number 2 – can you tell me where I can download these distributions from? Maybe someone from the forum would like to upload them and give a link? It would be so beautiful and easy after all these ssh rituals)