OTA updates:

The builds are in OTA format so they dont include bootloader
and radio images so make sure you have flashed latest bootloader
and radio image from google stock images

bootloader-oriole-slider<version>.img
radio-oriole<version>.img

First time install:

Bear with me that I simply dont care about Windooze users here
just google for any specific instructions there.

Also I will skip anything regarding bootloader unlock here
and assume you did this before.

Extract file payload.bin from <ota-file>.zip

Use payload dumper to extract boot.img and vendor_boot.img from that
payload.bin file

There are different impls of payload dumper eg
https://pypi.org/project/payload-dumper/
https://github.com/ssut/payload-dumper-go

Make sure you use the latest version of Android SDK platform tools
https://developer.android.com/studio/releases/platform-tools

Make sure you are familiar with basic usage of fastboot and adb
commands

If you care about anything on the device - NOW its the time to create
a backup somewhere save

Test adb working:

> adb devices
List of devices attached
<serialnumber>	device

Reboot into bootloader:

> adb reboot bootloader

Check fastboot showing device in fastboot mode:

> fastboot devices
<serialnumber>	fastboot

Flash minimal recovery:

> fastboot flash boot boot.img
> fastboot flash vendor_boot vendor_boot.img

Start recovery:

> fastboot reboot recovery

Wait until you see Android mascot on his back with the words 'No command' underneath.
Press and hold the Power key and then press the Volume up key once while still holding
down the Power key.

Device will enter recovery
Check adb showing device in recovery mode

> adb devices
List of devices attached
<serialnumber>	recovery

Select 'Apply update from adb'

Follow instructions and run adb command

> adb sideload <ota-file>.zip

Select 'Wipe data/factory reset'

Select 'Reboot system now'

You should also flash the second slot once your setup is complete
Either repeat the steps from above

adb reboot recovery
Apply update from adb
adb sideload <ota-file>.zip
Reboot system now

Ofc you dont need to wipe data again then

You can also just wait for the next OTA update to be available
and use the app which will install the update on the other slot

OTA updates of running system:

Simply use OTA app in Control Center -> System updates