This demo uses a simple scenario involving two branches to show what happens when changes clash.

Step 1: Set Up Your Repository

1. Create a new directory for your project and navigate into it:

   mkdir git-demo
   cd git-demo

2. Initialize a new Git repository:

   git init

Step 2: Create a Base File

1. Create a new file called example.txt and open it in a text editor.
2. Add some content to the file, such as:

   Hello, world!
   This is a Git merge conflict demonstration.

3. Add and commit the file to the repository:

   git add example.txt
   git commit -m "Initial commit"

Step 3: Create Branches

1. Create and switch to a new branch called feature:

   git branch feature
   git checkout feature

2. Make changes to example.txt in the feature branch. For example, change the second line to:

   This is a feature branch version.

3. Commit the changes:

   git add example.txt
   git commit -m "Update from feature branch"

Step 4: Create a Conflict

1. Switch back to the main branch:

   git checkout main

2. Make different changes to the same line in example.txt. Change the second line to:

   This is the main branch version.

3. Commit these changes:

   git add example.txt
   git commit -m "Update from main branch"

Step 5: Attempt to Merge and Resolve Conflict

1. Try to merge the feature branch into the main branch:
   This will result in a merge conflict because both branches modified the same line of the same file.

   git merge feature

2. Open example.txt and you will see something like this:

   Hello, world!
   <<<<<<< HEAD
   This is the main branch version.
   =======
   This is a feature branch version.
   >>>>>>> feature

3. Resolve the conflict by editing the file to incorporate both changes or choose one over the other. For example:

   Hello, world!
   This is the merged version from both branches.

4. Add the resolved file to the staging area and complete the merge:

   git add example.txt
   git commit -m "Resolved merge conflict"

This step-by-step guide provides a hands-on way to demonstrate and resolve merge conflicts, helping you understand how Git handles simultaneous changes to the same part of a file by different branches.