docs: Update contributing guide

CONTRIBUTING.md

@@ -43,6 +43,18 @@ pnpm install
 pnpm build
 ```
 
+# Files and Directories Created After Installation
+
+After running `pnpm install` and `pnpm build`, the following files and directories are created:
+
+- Forc Repository:
+  - Located at `internal/forc/sway-repo`.
+  - Contains the source code for the version of `forc` you are using.
+
+- Fuel-Core Repository:
+  - Located at `internal/fuel-core/fuel-core-repo`.
+  - Contains the source code for the version of `fuel-core` you are using.
+
 # Developing
 
 For building everything in watch-mode, run:
@@ -109,6 +121,70 @@ See also:
 
 - [Developing](#developing)
 
+# Working with Unreleased Forc and Fuel-Core Functionality
+
+When you need to work with unreleased versions of `forc` or `fuel-core`, you can specify a git branch instead of a version number.
+
+## Using Unreleased Forc
+
+To use an unreleased version of `forc`:
+
+1. **Edit the `VERSION` File**
+Open the `internal/forc/VERSION` file and replace the version number (e.g., 0.59.0) with the desired git branch:
+
+    ```text
+    git:some/branch-name
+    ```
+1. **Install and Build**
+To download and build `forc` from the specified branch after updating `VERSION` file, run:
+
+    ```sh
+    pnpm install
+    pnpm build
+    ```
+
+The following directory will be updated or created: `internal/forc/sway-repo`
+
+## Using Unreleased Fuel-Core
+
+Similarly, to use an unreleased version of `fuel-core`:
+
+1. **Edit the `VERSION` file:**
+Open the `internal/fuel-core/VERSION` file and replace the version number with the desired git branch:
+
+    ```text
+    git:some/branch-name
+    ```
+1. **Install and Build**
+To download and build `fuel-core` from the specified branch after updating `VERSION` file, run:
+
+    ```sh
+    pnpm install
+    pnpm build
+    ```
+
+The following directory will be updated or created: `internal/fuel-core/fuel-core-repo`
+
+# Switching Back to Standard Binaries
+
+If you switch back to using standard binaries you might encounter issues where the SDK still uses the previously downloaded unreleased binaries.
+
+## Resolving the Issue
+
+To resolve the issue and ensure the SDK uses the correct binaries:
+
+1. **Delete the downloaded repositories**
+
+    ```sh
+    rm -rf internal/forc/sway-repo
+    rm -rf internal/fuel-core/fuel-core-repo
+    ```
+1. **Reinstall and build.**
+    ```sh
+    pnpm install
+    pnpm build
+    ```
+
 # Testing
 
 In order to run tests locally, you can run the following commands: