Zabbix Template Modification

I'm looking for a Zabbix expert to help with the following tasks:

1. Modify an existing trigger:
- Customize the trigger expression, alert message, or severity level as needed.

2. Create a new item and corresponding trigger:
- Define the new item parameters.
- Set up a new trigger with a customizable expression.

Ideal skills and experience:
- Proficiency in Zabbix
- Experience with trigger customization
- Knowledge of item creation and management

Please provide examples of previous Zabbix work.