Query from Daily Notes

Hi there,

I use daily notes to note down what is happening throughout a day.
Normally i either use a Header with the name of the project or People i collaborate and below i use a series of bullets and tasks
I use tags or links to [[Projects]] or [[People]] that i work with.

I still dont know how i can filter per project or person.
As I understand queries is how it should be done, using dataview but i find it too difficult to understand how to define a query.

Any advise or approach how you do it, i would really really appreciate.
Thank you in advance!