Add Setting Buttons section to Rich Presence Social SDK guide (#8255)

Documents ActivityButton usage with C++, Unity, and Unreal examples,
and notes that buttons are only visible to other users — not yourself.

Author: markmandel

developers/discord-social-sdk/development-guides/setting-rich-presence.mdx

@@ -189,6 +189,61 @@ activity.SetAssets(assets);
 
 ---
 
+## Setting Buttons
+
+You can add up to two custom buttons to a player's Rich Presence. Each button has a label and a URL, making them a direct call to action for anyone viewing the presence — link out to your game's store page, website, or community server.
+
+<CodeGroup>
+
+```cpp C++
+discordpp::ActivityButton buyButton;
+buyButton.SetLabel("Buy On Steam!");
+buyButton.SetUrl("https://store.steampowered.com/app/AppID/GameName/");
+
+discordpp::ActivityButton communityButton;
+communityButton.SetLabel("Join the Community!");
+communityButton.SetUrl("https://discord.gg/your-discord-url-or-id");
+
+activity.AddButton(buyButton);
+activity.AddButton(communityButton);
+```
+
+```csharp Unity
+ActivityButton buyButton = new ActivityButton();
+buyButton.SetLabel("Buy On Steam!");
+buyButton.SetUrl("https://store.steampowered.com/app/AppID/GameName/");
+
+ActivityButton communityButton = new ActivityButton();
+communityButton.SetLabel("Join the Community!");
+communityButton.SetUrl("https://discord.gg/your-discord-url-or-id");
+
+activity.AddButton(buyButton);
+activity.AddButton(communityButton);
+```
+
+```cpp Unreal
+UDiscordActivityButton* BuyButton = NewObject<UDiscordActivityButton>();
+BuyButton->Init();
+BuyButton->SetLabel("Buy On Steam!");
+BuyButton->SetUrl("https://store.steampowered.com/app/AppID/GameName/");
+
+UDiscordActivityButton* CommunityButton = NewObject<UDiscordActivityButton>();
+CommunityButton->Init();
+CommunityButton->SetLabel("Join the Community!");
+CommunityButton->SetUrl("https://discord.gg/your-discord-url-or-id");
+
+Activity->AddButton(BuyButton);
+Activity->AddButton(CommunityButton);
+```
+
+</CodeGroup>
+
+<Tip>
+Buttons are only visible to **other users** — you cannot see buttons on your own Rich Presence. To test that your buttons are working, use a second account or ask a friend to view your profile.
+</Tip>
+
+---
+
 ## Configuring Status Text
 
 By default, Rich Presence will display the game's name in the user's status text. You can override this behavior by setting a status display type.
@@ -316,13 +371,15 @@ import {InboxIcon} from '/snippets/icons/InboxIcon.jsx'
 
 ## Change Log
 
-| Date           | Changes         |
-|----------------|-----------------|
-| March 17, 2025 | Initial release |
+| Date           | Changes                       |
+|----------------|-------------------------------|
+| March 31, 2026 | Added Setting Buttons section |
+| March 17, 2025 | Initial release               |
 
 {/* Autogenerated Reference Links */}
 [`Activity`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Activity.html#ae793d9adbe16fef402b859ba02bee682
 [`ActivityTypes`]: https://discord.com/developers/docs/social-sdk/namespacediscordpp.html#a6c76a8cbbc9270f025fd6854d5558660
 [`Client::Connect`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#a873a844c7c4c72e9e693419bb3e290aa
 [`Client::SetApplicationId`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#ad452335c06b28be0406dab824acccc49
-[`Client::UpdateRichPresence`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#af0a85e30f2b3d8a0b502fd23744ee58e
+[`Client::UpdateRichPresence`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1Client.html#af0a85e30f2b3d8a0b502fd23744ee58e
+[`ActivityButton`]: https://discord.com/developers/docs/social-sdk/classdiscordpp_1_1ActivityButton.html