1 - How to start ? What have to be done the first?
Please note that there is no ideal or logical order to start viewing the training, so you can watch them according to your preference, or simply follow the sequence on which they are provided.
One tip could be for you to start with the videos about topics you are already familiar with, so you can understand the structure of the presentation. This way you can have a better experience when watching videos on topics new to you.
2 - How to start auditing the company on Information Security?
The internal audit can be performed by the organization's own employees, provided they have the competence and do not audit their own work. Or you can contract a third party to perform the audit.
As for choosing a third party to perform the audit, you should consider at least these criteria.
Experience and skills
Understanding your industry
These articles will provide you a further explanation about internal audit:
5 criteria for choosing an ISO 22301 / ISO 27001 consultant <a href="https://advisera.com/27001academy/blog/2013/03/25/5-criteria-for-choosing-a-iso-22301-iso-27001-consultant/?icn=free-blog-27001&ici=top-5-criteria-for-choosing-an-iso-22301-iso-27001-consultant-txt