How to turn on networking from rescue boot

So...  I did a "sudo dnf upgrade" and things seemed to do well.  
However, when I rebooted, it hangs on bootup with the statment "Holding 
until bootup processes complete" or something like that -- I'm doing 
this from memory.  I tried with a couple of older kernels, but they also 
hung.

I assume that this is some transient thing associated with the upgrade.  
Over the years, I've had glitches appear on an upgrade and disappear on 
the next upgrade.  Accordingly, I'd like to boot into rescue mode and 
see if I can upgrade again.

However, I've forgotten how to turn on wifi networking from rescue mode.

Can anybody point me to a tutorial?

Thanks,

billo