Setup

for 2.79 official version 1.2.8, 2.8 official 1.2.81 version skip download

Download lastest from github

Download page
In Code tab, use "Clone or download" and choose "Download Zip"
save the zip.

Setup the addon

In blender open user preference dialog.

Choose downloaded zip so blender install the addon

Activate archipack addon

Download and setup default material library

Setup material library
Download default cycles material library sample

Setup default presets thumbnails

Thumbs where not allowed in disto to reduce size. You'll have to render them once at setup.
Addons folders are not writeable by default, so this tool does move presets on user profile.

Archipack 1.3.5+ / Archipack official 1.2.81 for blender 2.8

Use "Render preset thumbs" in file -> user preferences -> Add-ons -> archipack -> Setup actions, then restart blender.

Archipack official 1.2.8 for blender 2.79

See detailled instructions to render thumbs