One more point.

I have found that connecting to a wifi while in "try-Ubuntu" mode before
clicking the "install Ubuntu" icon will make updating while installing
work if you need to use a password or log into a network page to get
service. Once logged in a short interruption will not be a problem
because most networks have a timeout timer that keeps your computer
logged in.

Typically I try Ubuntu before I install because I can test the computer
for hardware that becomes a problem. If everything works in this mode
then installing while connected to the Internet has been little problem.
I also like to start the gparted editor and modify the hard-drive
manually before I start the install.

One more point. I like to have a wifi dongle with supported chipset
handy before I install. I don't have access to a LAN cable. Another way
is a 3G or 4G dongle works well. In the past they were somewhat of a
problem but not much anymore. If the 3G dongle fails to show a memory
device will show and un-mounting it uncovers the 3G device.

All in all my first experience with Ubuntu was a nightmare because of
unsupported WiFi, but today is only a minor inconvenience and only on a
few chip sets.