Edit lab setup and contributing policy

Signed-off-by: Hartanto Ario Widjaya <tanto259@users.noreply.github.com>

Author: tanto259

COBOL Programming Course #2 - Advanced Topics/Labs/README.md

@@ -25,7 +25,7 @@ To set up your own environment for the Course,
 - You will need to copy the members from **cbl** to your own PDS. The Course Document and JCL assume that the PDS is `&SYSUID..CBL`.
 - You will need to copy the members from **jcl** to your own PDS. The Course Document assumes that the PDS is `&SYSUID..JCL`.
 - You will need to make sure that the procedures DB2CBL and DB2JCL are added from **jclproc** to your procedure library. 
-- You will need to make sure that the IBM-supplied procedure DSNUPROC is an IBM-supplied procedure. A copy is available on **jclproc**.
+- You will need to make sure that the IBM-supplied procedure DSNUPROC is available in your procedure library. A copy is available on **jclproc**.
 
 Note that the JCL references the following data sets,
 - `&SYSUID..CBL` where the COBOL source codes are stored

CONTRIBUTING.md

@@ -9,7 +9,7 @@ The primary intent of the COBOL Programming Course is to offer free and accessib
 For major changes, please open an issue first to discuss what you would like to change. All contributions should be made with the primary intent of the course in mind.
 
 ## Sign all of your git commits!
-All contributions must align with the [Open Mainframe Project contribution guidelines](https://github.com/openmainframeproject/tac/blob/master/process/contribution_guidelines.md), including having a DCO signoff on all commits.
+All contributions must align with the [Open Mainframe Project contribution guidelines](https://github.com/openmainframeproject/tac/blob/master/process/contribution_guidelines.md), including having a [DCO signoff](https://developercertificate.org/) on all commits.
 
 Whenever you make a commit, it is required to be signed. If you do not, you will have to re-write the git history to get all commits signed before they can be merged, which can be quite a pain.
 
@@ -40,3 +40,15 @@ If you are committing via the GitHub UI directly, check out these [useful tools]
 ## Pull Requests
 - All contributions must be reviewed by a [committer](COMMITTERS.csv) 
 - Anyone can comment on a pull request to request delay on merging or to get questions answered.
+
+## License and Copyright
+All documentation and lab codes for the COBOL Programming Course will be made available under the [Creative Commons Attribution 4.0 International License](LICENSE).
+
+All lab codes need to include a header to clearly show this information in [SPDX short-form identifier](https://spdx.dev/ids/) along with a general copyright statement as shown below:
+
+```
+/* Copyright Contributors to the COBOL Programming Course
+/* SPDX-License-Identifier: CC-BY-4.0
+```
+
+For binary or configuration files that do not support comments, the license may be omitted. If comments are supported, the license header should be included.