Install addon manually

@bonnietwin
that’s very well meant of you. i’ve already read the wiki. but to be honest, for me these are just bohemian villages.
the addons I have are available as .ipfire files, which used to be in pakfire a very long time ago.
the wiki didn’t really answer my question as a layman. i have no knowledge of linux and just wanted to know where to put the addon packages and which command(s) to use for the installation.