The GDPR provides for various requirements that companies need to comply with.
Non-Compliance with these requirements can lead to fines of up to 2% resp. 4% of the world wide turnover of a company. Take a moment and make yourself familiar with the most important compliance clusters:
Intro: What are the most important facts about the respective topic?
Requirements: Which legal regulations must be considered?
Duties: Which specific measures need to be implemented?