Flashing UT manually

[Ub]

Hello everyone,
I need to know how to flash UT on a nexus 5 without using Ubports-installer, the aim is to better understand UT and also flashing without internet connection.
I already have the boot and recovery images (that I got with the installer after flashing to another nexus 5).

Is it enough if I just flash these images (with fastboot flash boot boot.img and fastboot flash recovery recovery.img) ? I mean, after unlocking the phone and installing TWRP of course.

I don't know if there is a risk to brick it, that's why I ask you first.

[arubislander]

@ub the installer is open source. I guess one way of finding out the manual steps would be to read the source of the installer and manually reproduce the steps it takes.