The regulations apply to computer based data, client records stored electronically and electronic marketing.
If you don’t understand what you need to do, don’t use a computer/smart phone to communicate with clients, Of course you’ll already have your friends details, that’s ok,. Don’t save any emails or texts about appointments - delete them. Don’t send out marketing emaiis or texts. Don’t use an app based appointment system nor enter client info on to bookkeeping spreadsheets. Just keep a manual diary to track appointments and keep it in a locked drawer if it’s not in use. Remember not to store any new client contact details on your phone, write it in your diary instead.
GDPR is covered in the basic education all professionals are expected to complete in addition to skill based training. If you buy an up to date, used text book they’ll be an outline to get you started. Most Councils offer training courses to business start ups or at least have a department that can suggest courses available. It is really helpful to be able to ask questions and meet other start ups with similar issues to your own.