I am slightly confused
I currently have Pillars of Eternity Heroes Edition running contentedly on my PC
I recently purchased the
"PILLARS OF ETERNITY: THE WHITE MARCH - EXPANSION"
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Using GOG Galaxy
Clicking on the Pillars of Eternity game in my library displays
INSTALLED
English - 3.05 - 0 DLCs
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Using my on line GOG account
Clicking on the Pillars of Eternity game in my library displays

Pillars of Eternity (Part 1 of 3) 3.05 (gog-18) 32 MB
Pillars of Eternity (Part 2 of 3) 3.05 (gog-18) 3.9 GB
Pillars of Eternity (Part 3 of 3) 3.05 (gog-18) 2.6 GB
Patch 3.03 3.02 (gog-15) -> 3.03 (gog-16) 15 MB
Patch 3.04 3.03 (gog-16) -> 3.04 (gog-17) 12 MB
Patch 3.05 3.04 (gog-17) -> 3.05 (gog-18) 7 MB

DLC Downloads
Pre-Order Bonus Item and Pet (gog-13) 7 MB

The White March - Part I - Pillars of Eternity: The White March - Part I (Part 1 of 2) 3.05 (gog-18) 32 MB
The White March - Part I - Pillars of Eternity: The White March - Part I (Part 2 of 2) 3.05 (gog-18) 2.6 GB
The White March - Part I - Patch 3.03 3 MB
The White March - Part I - Patch 3.04 5 MB
The White March - Part I - Patch 3.05 2 MB

The White March - Part II - Pillars of Eternity: The White March - Part II (Part 1 of 2) 3.05 (gog-18) 32 MB
The White March - Part II - Pillars of Eternity: The White March - Part II (Part 2 of 2) 3.05 (gog-18) 1.9 GB
The White March - Part II - Patch 3.03 3.02 (gog-15) -> 3.03 (gog-16) 3 MB
The White March - Part II - Patch 3.04 3.03 (gog-16) -> 3.04 (gog-17) 4 MB
The White March - Part II - Patch 3.05 3.04 (gog-17) -> 3.05 (gog-18) 1 MB
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Working through a number of other posts I suspect I need to do the following
Download the ten "The White March" DLC files
(Do they need to be placed in any particular location ?)
Run each of them in order

I'm only asking in case someone might say
"Don't be a prat, there's a download and install option tucked away on a set up page somewhere"
or something similar

Any patient and helpful replies gratefully received
Any sniggering and pointing accepted with good grace

Ah yes! The big button with MORE in capital letters on it
Never thought of trying that
Doh!

Many thanks Hickory

Sadly for me, GOG galaxy does not show or acknowledge the DLC, so i am stuck waiting for support.

I Found a fix, downloading it from the GOG page, seems to make GOG galaxy notice the file and makes the DLC option apear in GOG galaxy

Help, I purchased Pillars Of Eternity Definitive Edition on Gog Galaxy, installed the main game loaded it up and said White March expansions not installed. So I went into the game on Gog Galaxy found the separate White March pt I and II files and installed them, said install was completed. Or so I thought. Booted up the game next day still says White March not installed. WTF is going on?