Clarify new branch creation steps in documentation

Updated instructions for creating a new branch to clarify naming and source selection.

Author: ashis-baral

content/pull-requests/how-tos/commit-changes/managing-branches-within-your-repository.md

@@ -32,9 +32,9 @@ Create a branch for a separate place to work on changes before opening a pull re
 1. Click **New branch**.
 
    ![Screenshot of the "Branches" page for a repository. A green button, labeled "New branch", is highlighted with an orange outline.](/assets/images/help/branches/new-branch-button.png)
-1. Under "Branch name", type a name for the branch.
-1. Under "Branch source", choose the repository and branch to base your new branch on.
-1. Click **Create branch**.
+1. Under "New branch name", type a name for the branch.
+1. Under "Source", choose the branch to base your new branch on.
+1. Click **Create new branch**.
 
 ### Creating a branch using the branch dropdown