This setup allows customers to book onsite appointments online while Odoo automatically assigns one of your technicians. This allows for more automation in the company and thus less burden to plan the intervention tasks.

Video: https://drive.google.com/file/d/1O1vIrDKFU9fTrUzhHh802bEtXLNhmWiR/view?usp=sharing

Configuration (screenshot) : 

1. configure an appointment type 
2. based on users
3. select the users (technicians)
4. choose the assignment method
5. prepayment → configure this product to be a service creating a field service task

Note that ecommerce should be installed as well.

Hope this helped !