How can I practice meditation? Which online course?

Hi everyone, I (42F) got into yoga and meditation maybe 10 years ago to great effect. I felt like a different person: calm, non reactive, peaceful. Now I want to get back into it, by practicing meditation at home. Ideally I want to use a guided meditation. I have the Calm app, but I can't find meditation options in the app that are longer and they all focus on issues like anxiety or work stress or sleep... I think 20mins is a good length, then build up, is that right? Id love any suggestions for online tools I could use to get back into a regular mediation practice. Thanks so much