Hello Meriem and welcome to the forum,
To start, please download the standard ANSI/ESD S20.20 - ESD process control from the ESD Association website. The requirements for an ESD control program are there. You will also need a copy of TR53 - Compliance Verification from the ESD Association. Once you have these two documents you have most of the information needed to establish and ESD control program.
Of course that was the easy part. The next part is to put in place the requirements such as a documented program, training, product qualification and a compliance verification plan.
Then you need to establish the Electrostatic Protection Area (EPA) with the control items that are needed.
If you need information, see the https://www.esda.org/training-and-education/ for all the courses that are offered online. They will help with technical issues.
For your facility to become certified, see https://www.esda.org/certification/eosesd-association-esd-facility-certification/. Here you can view certification overview and see the accredited certification bodies. Contact one of them to conduct the assessment that can lead to a certificate. Work with the certification body to arrange the formal assessment or have a pre-assessment done.
If you have any other questions, please feel free to post them here.