Can you help me decide what to include in my privacy notice?

The GDPR sets out the information you should supply and when individuals should be informed.The information you supply about the processing of personal data must be: 
concise, transparent, intelligible and easily accessible;written in clear and plain language, particularly if addressed to a child; andfree of charge.

https://ico.org.uk/for-organisations/education/education-gdpr-faqs/

As you can see above,
It mught be necessary to make concise, transparent, intelligible and so on
Notice. The thing is that it should be eaily  
understand.