Existence: listener question

I recently caught up with your 5 days video series. In one of the videos, you talked about how some people say ‘The I doesn’t exist’ or ‘I don’t exist’ – and then you said something like: ‘That’s not true you do exist.’ My mind’s voice went ‘I exist!’ as if this was amazing, new news. Then it went into confusion – logically I know I exist in that I’m here and the ‘I’ that I usually experience doesn’t really exist, it’s a load of beliefs, thinking, feelings that isn’t an entity but can you say more about this for the mind and to help have a sense of what/who exists and how we can ground this?  Thank you.