How to fetch data from firestore database using Javascript/Web?

 db.collection("schools")
   .doc("St. Francis Xavier's")
   .collection("students")
   .add({
          Name:"Manoj Shetty",
          Age:"21",
          Address:"Sakaleshpur"
       )}

In this type of firestore collection, 1.How to fetch the names of students who belong to "St. Francis Xavier's"? 2. How to fetch the details of particular student who belong to "St. Francis Xaviers"? 3. How to fetch details of all students from all schools?