Merge pull request #131 from C2SM/https_address

Add note about using https address for users who don't have an SSH key

Author: AnnikaLau

beginner/Exercise_1_basic_commands.md

@@ -69,6 +69,8 @@ If you are satisfied with your current directory, use the following command to c
 git clone [email protected]:C2SM/git-course.git 
 ```
 
+> **Note:** If you did not set up an SSH key linked to your GitHub account, you will have to use `https://github.com/C2SM/git-course.git` instead for cloning the repository.
+
 You can now navigate into it with
 
 ```bash
@@ -262,4 +264,4 @@ Date:   Tue Feb 23 16:09:54 2021 +0100
 ```
 
 We see the unique hash of each commit, its author, and the date of the commit.
-These are all very useful things as we will see later in this course.
+These are all very useful things as we will see later in this course.