Ubuntu 20.04

Tue May 5 12:56:58 UTC 2020

Hello everyone.  I am using Ubuntu 2020 with a Dell.
When installing Ubuntu mate 2020.04 yesterday, I pressed f 12 to get to the boot menu.
Then went to what I thought was the dvd choice.
Since I could not bring up Orca for several attempts, I used Be My Eyes.
The volunteer said that after I pressed f 12, a language choice prompt appeared.
Then the choice whether to use Ubuntu before installing, or to install appeared.
After entering on use before installing I then brought up Orca with super alt s.
Should I have been able to bring up Orca before those other choices?
Is this installer markedly different than with Ubuntu 2018.04?
Had I not had Be My Eyes, how would I have known what to do in this situation?