Create dynamic link using Firebase Functions

Im trying to set up a dynamic link that is auto created when a item is added to a the firestore database. 1) How do I get the dynamic link to create using a cloud function? 2) When the link is generated how do I add it to the database?

    >     import * as functions from 'firebase-functions'; 
    >     import * as admin from 'firebase-admin'; 
    > 
    > 
    > admin.initializeApp(functions.config().firebase);
    > 
    > 
    > export const link_gen =
    > functions.firestore.document('/Users/{userID}/Events/{eventsID}').onCreate((snapshot,
    > context) => {
    >     console.log("Event Created - Starting Link Generaction")
    >     console.log("Starting Link Gen For Guest Upload")
    > 
    >     //getting room and event data strings
    >     const userID = context.params.userID
    >     const eventID = context.params.eventsID
    >     console.log(userID)
    >     console.log(eventID)
    > 
    > 
    >     //getting all data in the new event
    >     const data = snapshot.data()
    >     console.log(data)
    > 
    >     //creating the dynamic link service from firebase
    >     POST https://firebasedynamiclinks.googleapis.com/v1/shortLinks?key=APIKEY
    >     Content-Type: application/json
    >     console.log("running")
    >     {    "longDynamicLink": "https://woke.page.link/Pages/gh/main.html?u=" + userID + "&e=" +
    > eventID;
    >     }
    > 
    > 
    > });