Open html file base on net/http package in Go

I am a beginner for Go. I try to build a static web server in my local computer. Actually, I have been read How do you serve a static html file using a go web server?

My question is, if I have a "Home.html". I want to open "Home.html" when I link "localhost:7777".

It's like "index.html", but I want to replace "index.html" with "Home.html".

Here is my code:

package main
import (
    "fmt"
    "net/http"
    "log"
)

func helloHandler(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "hello world!")
}
func main() {

    http.HandleFunc("/", helloHandler)
    // 
    err := http.ListenAndServe(":7777", nil)
    if err != nil {
        log.Fatal("ListenAndServe", err)
    } else {
        log.Println("listen 7777")
    }
}

How do I re-write this code?

What keywords for this problem?

Thanks a lot. ^^