diff --git a/ReadMe.md b/ReadMe.md
index cd96bf3..e9f54b0 100644
--- a/ReadMe.md
+++ b/ReadMe.md
@@ -20,6 +20,8 @@ automation tools assume P4, which can be inconvenient).
   * Almost everything is compatible with Win10 built-in PS 5.1 but 7 is better, and platform independent
 * PsIni module installed (library for reading INI files easily)
    * Run `Install-Module PsIni` in a Powershell console
+* Itch's [`butler` tool](https://itch.io/docs/butler/) if you wish to release to Itch.io
+* The [Steamworks SDK](https://partner.steamgames.com/doc/sdk) if you wish to release on Steam
 
 
 If these tools are useful, please consider :heart: **[Supporting my work on Patreon!](https://www.patreon.com/stevestreeting)**
diff --git a/doc/Release.md b/doc/Release.md
index 7f7fe9e..cf6f9fb 100644
--- a/doc/Release.md
+++ b/doc/Release.md
@@ -1,3 +1,69 @@
-# Release Scripts
+# Release Script
 
-TODO
\ No newline at end of file
+The release script `ue4-release.ps1` takes previously packaged builds (see
+[Packaging Script](./Package.md)) and uploads them to publishing services; 
+currently Itch.io and Steam.
+
+You will need to install the [Steamworks SDK](https://partner.steamgames.com/doc/sdk)
+to release on Steam, and the [Itch Butler tool](https://itch.io/docs/butler/) to
+release on Itch.
+
+This script uses configuration stored in [`packageconfig.json`](./PackageConfig.md).
+
+```
+  ue4-release.ps1 -version:ver -variants:v1,v2 -services:steam,itch [-src:sourcefolder] [-dryrun]
+
+  -version:ver        : Version to release; must have been packaged already
+  -variants:var1,var2 : Name of variants to release. Omit to use DefaultVariants
+  -services:s1,s2     : Name of services to release to. Can omit and rely on ReleaseTo
+                        setting of variant in packageconfig.json
+  -src                : Source folder (current folder if omitted), must contain packageconfig.json
+  -dryrun             : Don't perform any actual actions, just report what would happen
+  -help               : Print this help
+```
+
+
+## Uploading all builds at once
+
+The only mandatory argument is the version number. With only that argument, 
+the script will process all the [default variants](./PackageConfig.md#defaultvariants)
+for this project and release any which have [release settings](./PackageConfig.md#defaultvariants).
+This allows you to push all your builds for a given version at once.
+
+## Uploading more selectively
+
+Alternatively you can limit the packages you upload using the `-variants` and
+`-services` arguments; if supplied, only matching variants and publishing services
+will be processed.
+
+## Authentication
+
+This script will call the Itch `butler` tool and/or the Steam `steamcmd` tool. 
+These have their own authentication; you will be prompted as needed but if you
+want to guarantee no prompts during running, you should log in to the services
+on the command line beforehand.
+
+### Logging in to Itch
+
+```
+butler login
+```
+
+Your Itch authentication will be stored for future use after logging in.
+
+### Logging in to Steam
+
+```
+steamcmd +login user_name
+```
+
+The `SteamLogin` setting in [`packageconfig.json`](./PackageConfig.md)
+should be the same as the username you log in with here.
+
+## When builds go live
+
+There is some variation on when players can see your uploaded packages:
+
+* **Itch**: Packages go live as soon as Itch finishes processing them
+* **Steam**: Packages sit in the release queue until you explicitly release them
+  via the Steamworks web interface