To release on Steam:
Build a shipping copy of the game. Make sure the target folder is empty and BP_DebugGameSettings has all the variables unchecked.
Copy a "Shipping" build of the game into the Steam sdk that has BP_DebugGameSettings IsGameDebug? and all other flags set to false.
And paste a copy of the Credits.txt file into the same directory.
> For Example: C:\Unreal\Projects\sdk_162\tools\ContentBuilder\content
CopySteam_AppBuild4020030.vdf into into the Steam sdk's scripts directory. 
> For example: C:\Unreal\Projects\sdk_162\tools\ContentBuilder\scripts
Copy all the "depots" (e.g. Steam_DepotBuild4020031.vdf, SteamDLC_DepotBuild_Bronze.vdf, and etc) into into the Steam sdk's scripts directory. 
> For example: C:\Unreal\Projects\sdk_162\tools\ContentBuilder\scripts
Copy all the dlc directories into the tools\ContentBuilder folder of the sdk. 
> For example: dlc-bronze, dlc-silver, and dlc-gold directories in the Steamworks folder
Copy Steam_Installscript.vdf from the Steamworks folder in the project directory into the Steam sdk content directory. 
> For example: C:\Unreal\Projects\sdk_162\tools\ContentBuilder\content
Copy Steam_CardinalInstaller.exe from the Steamworks folder in the project directory into the Steam sdk content directory. 
> For example: C:\Unreal\Projects\sdk_162\tools\ContentBuilder\content
Then open Steam command. 
> For Example: C:\Unreal\Projects\sdk_162\tools\ContentBuilder\builder\steamcmd.exe
And login. 
> For example: login <account_name> <password>
Then build the depot (which uploads the project files in the content folder) For example: run_app_build ..\scripts\Steam_AppBuild4020030.vdf
Then quit. 
>For example: quit
After that, you will need to publish the changes on Steam by going to https://partner.steamgames.com/apps/builds/4020030 then selecting the "default" branch, preview change, entering a comment, then Set Build Live

To push an update on Steam if SteamCMD is already set up:
Build a shipping copy of the game. Make sure the target folder is empty and BP_DebugGameSettings has all the variables unchecked.
Copy a "Shipping" build of the game into the Steam sdk that has BP_DebugGameSettings IsGameDebug? and all other flags set to false.
> Keep the Steam_InstallScript.vdf and Steam_CardinalInstaller.exe files in the same directory. 
And paste a copy of the Credits.txt file into the same directory.
> For Example: C:\Unreal\Projects\sdk_162\tools\ContentBuilder\content
Then open Steam command. 
> For Example: C:\Unreal\Projects\sdk_162\tools\ContentBuilder\builder\steamcmd.exe
And login. 
> For example: login <account_name> <password>
Then build the depot (which uploads the project files in the content folder) For example: run_app_build ..\scripts\Steam_AppBuild4020030.vdf
Then quit. 
> For example: quit
After that, you will need to publish the changes on Steam by going to https://partner.steamgames.com/apps/builds/4020030 then selecting the "default" branch, preview change, entering a comment, then Set Build Live


Double Check:
1. Make sure it was a SHIPPING build with all the flags in  BP_DebugGameSettings set to false / unchecked.
2. Make sure the current Credits.txt files is copied into the root of the folder.