How to run a function line by line/How to run a function Asynchronously?

I am trying to run this function sequentially. The output should be:

latitude length,
lat length A,
lat length B

But the output I am getting is:

latitude length,
lat length B,
lat length A

I want to process this.adminService.getUserList().subscribe(res => {} first but it is getting processed after the completion of makeAnAPICall() function. My code is below:

 async makeAnAPICall():void {
     console.log("latitude length",this.latitude.length);
     this.latitude = [];
     this.longitude = [];
     delay(2000);

    await this.adminService.getUserList().subscribe(res => {
       for(let i =0; i < res.length; i++) {
         this.latitude.push(res[i].latitude);
         this.longitude.push(res[i].longitude);
       };
       console.log("lat length A",this.latitude.length)
     }); 
        
     console.log("lat length B ",this.latitude.length);
  }

You need to convert your observable to promise first.

async makeAnAPICall():void {
     console.log("latitude length",this.latitude.length);
     this.latitude = [];
     this.longitude = [];
     delay(2000);
     const res = await this.adminService.getUserList().first().toPromise();
   
       for(let i =0; i < res.length; i++) {
         this.latitude.push(res[i].latitude);
         this.longitude.push(res[i].longitude);
       };
       console.log("lat length A",this.latitude.length)
     console.log("lat length B ",this.latitude.length);
  }