Open the Steam Service using console command

This requires programming to create a blueprint node that can do so.

This documentation talks about the Game Overlay.
https://partner.steamgames.com/documentation/game_overlay

You don’t need any callbacks or call results from steam to trigger them, so if you follow this guide, you should get an idea on how to create a blueprint node to bring the steam overlay, and to set the steam web browser to a specific url.

Look at First Step with Steam.
I’d do some changes to prevent crashes.
From



if (SteamAPI_Init())
{
  const char* name = SteamFriends()->GetPersonaName();
  GEngine->AddOnScreenDebugMessage(-1, 5, FColor::Red, name);
}


to



if (SteamFriends() != nullptr) //Check that the Steam Pointers are initialized previously
{
  FString SteamName = SteamFriends()->GetPersonaName();
  UE_LOG(LogSteamworks, Log, TEXT("Steam Name of User: %s"), *SteamName);
}


I read somewhere that SteamAPI_Init() will try to recreate steam when you read it, so just checking the steam pointers are populateed should be enough. I think.
UE_LOG doesnt depend on the editor and is much better to print logs of what you are doing.

From the Steam API, what you are looking for is this



SteamFriends()->ActivateGameOverlay("Community");     //const char *pchDialog     //Check the Steam Api for more Options.


Or



SteamFriends()->ActivateGameOverlayToWebPage("https://www.unrealengine.com");       //const char *pchURL


How to create a blueprint Library.

If you want to pause the game when the steam overlay comes up, it’s more complicated, and involves more programming, but luckily for you, I struggled with that for a month and a half, and after I won, I wrote a throrough guide on how to achieve this.

Hope this helps.