More guidance for v2

CONTRIBUTING.md

@@ -16,7 +16,6 @@ Terminal.Gui uses the [GitFlow](https://nvie.com/posts/a-successful-git-branchin
 * The `develop` branch is where bug-fixes to v1.x happens. It is the default branch.
 * The `v2_develop` branch is where development on v2.x happens. 
 
-
 ### Forking Terminal.Gui
 
 1. Use GitHub to fork the `Terminal.Gui` repo to your account (https://github.com/gui-cs/Terminal.Gui/fork).
@@ -37,16 +36,23 @@ You now have your own fork and a local repo that references it as `origin`. Your
 
 ### Starting to Make a Change
 
-Ensure your local `develop` branch is up-to-date with `upstream` (`github.com/gui-cs/Terminal.Gui`):
+Figure out if your change will target v1 or v2. If you're not sure, ask in the [v2 disucssions here](https://github.com/gui-cs/Terminal.Gui/discussions/1940).
+
+For v1.x, use the `develop` branch. For v2.x, use the `v2_develop` branch.
+
+Prefix any local branches you create with `v1_` or `v2_` to indicate which version you're working on.
+
+Ensure your local branch is up-to-date with `upstream` (`github.com/gui-cs/Terminal.Gui`):
+
 ```powershell
 cd ./Terminal.Gui
-git checkout develop
-git pull upstream develop
+git checkout <develop/v2_develop>
+git pull upstream <develop/v2_develop>
 ```
 
 Create a new local branch:
 ```powershell
-git checkout -b my_new_branch
+git checkout -b <v1/v2>_my_new_branch
 ```
 
 #### Making Changes
@@ -94,6 +100,10 @@ remote:
 
 Follow the template instructions found on Github.
 
+If you are targetting v2, set the project to the [v2 Project](https://github.com/orgs/gui-cs/projects/1).
+
+4. If your change is a bug fix, consider whether you should submit a separate PR to the v1 (`develop`) or v2 (`v2_develop`) branch as well.
+
 ## Terminal.Gui Coding Style
 
 **Terminal.Gui** follows the [Mono Coding Guidelines](https://www.mono-project.com/community/contributing/coding-guidelines/). [`/.editorconfig`](https://github.com/gui-cs/Terminal.Gui/blob/b0a43ba338adf5ec069066e5a7dff8fea39b41db/.editorconfig) enforces this style in Visual Studio. Use `Ctrl-K-D` in Visual Studio to have it reformat code.