How to use “set_facts” in playbook example-03?

How to use “set_facts” module in ansible playbook example-03?

Here is the code to know about the set_facts playbook module in ansible with examples 03 :

---
 # YAML documents begin with the document separator ---

# the minus in YAML this indicates a list item. The playbook contains a list
# of plays, with each play being a dictionary
-
# Target: where our play will run and options it will run with
hosts: all

# Task: the list of tasks that will be executed within the play, this section
# can also be used for pre and post tasks
tasks:
  - name: Set our installation variables for Oracle and CentOS
    set_fact:
      webserver_application_port: 80
      webserver_application_path: /usr/share/www
      webserver_application_user: root
    when: ansible_distribution == 'OracleLinux'

  - name: Set our installation variables for Ubuntu
    set_fact:
      webserver_application_port: 8080
      webserver_application_path: /local/nginx
      webserver_application_user: nginx
    when: ansible_distribution == 'Ubuntu'

  - name: show pre-set distribution based facts
    debug:
      msg: "webserver_application_port:{{ webserver_application_port}}       webserver_application_path:{{webserver_application_path}} webserver_application_uuser:{{ webserver_application_user}}"

# three dots indicate the end of a YAML document
...