How to download locally those packages that are usually installed by sudo apt-get in order to install without the Internet?

Question

ubuntu

How did you do it when there were problems with the Internet?
I make myself instructions for deploying a GUI (DE + VNC) anywhere, through fire and water - even on a server (which is someone else's and has just been rented or taken from somewhere else), even on a virtual machine.
Therefore, you cannot immediately take Xubuntu / Lubuntu. It is clean ubuntu that is taken, and packages are installed on it - the DE itself and all sorts of gadgets - some kind of notepad, some utility that performs the functions of a Windows task manager (gnome-system-monitor, most likely), etc.
As a DE, I will choose lxde or xubuntu-desktop (rather the first one), they will be installed by apt-get.
But what if the server is so poor that access to the repository is closed (I emphasize that it can be closed not on the server itself, but on its owner in the switching equipment, so that you won’t ask not to open it) or is it a computer without the Internet?
Obviously, somehow download all the packages locally, upload them there and install them in this way.
(And it is also desirable to be able to create your own repository on some host that will not be blocked on a poor server, upload these packages to that host, and get them from there through the same apt-get. But this is already the case.)

Answer 1

Here the problem is more likely to arise in the resolution of dependencies when installing a package ... how many packages will lxde pull with it?
Well, locally mirror the apt-mirror repository to help ..

Answer 2

I don’t know about Ubuntu, but Debian has disk images ftp.psn.ru/debian-cd/9.3.0/amd64/iso-dvd
in /etc/apt/sources.list you write such local images and it walks on them.
So they worked while the Internet was a luxury, disks flew back and forth