Update CONTRIBUTING.md

Signed-off-by: Jan Kowalleck <[email protected]>

Author: jkowalleck

CONTRIBUTING.md

@@ -5,6 +5,19 @@ But please read the
 [CycloneDX contributing guidelines](https://github.com/CycloneDX/.github/blob/master/CONTRIBUTING.md)
 first.
 
+## Issues
+
+When creating a new issue, please select the appropriate issue type from the available templates and fill out the provided form.  
+These templates ensure that all necessary information is captured consistently.
+
+## Pullrequests
+
+When opening a pull request, use the repository’s pull request template and complete all required fields.  
+Keep each pull request focused on a single topic or problem.
+
+Every pull request must reference an existing issue that it aims to address.  
+If no issue exists for your topic, please create one first using the appropriate issue template, then link your pull request to it.
+
 ## Setup
 
 To start developing simply run to install dev-dependencies and tools: