Creating a project with Go modules - go

Question

I'm trying to understand Go modules and create a simple hello world program. Go version: 1.16.2
/project1
/project1/main.go
/project1/helpers/helpers.go
helpers.go will contain some utility method like:
package ???
import "fmt"
func DoSomething() {
fmt.Println("Doing something in helpers.go")
}
main.go will use methods from helpers.go like this:
package main
import "??"
func main() {
helpers.DoSomething()
}
VSCode is not allowing me to do this and has a red underline on helpers.
What am I missing here? How can I achieve this?
Edit 1: Adding go.mod and package names:
So I ran go mod init helpers in /helpers folder and came out with this:
/project1/helpers/helpers.go
/project1/helpers/go.mod
go.mod
module helpers
go 1.16
My main.go now looks like this:
package main
import (
"fmt"
"helpers"
)
func main() {
fmt.Println("blah")
helpers.DoHelperMethod()
}

Answer 1

Your project should have only one go.mod file and it should be in the root of the project. You can cd into the project's directory and do go mod init <module_name> where <module_name> in your case can be project1.
For example, once you've initialized the module, your project should look something like the following:
/project1/helpers/helpers.go
/project1/main.go
/project1/go.mod
go.mod
module project1
go 1.16
main.go
package main
import "project1/helpers"
func main() { helpers.DoHelperMethod() }
helpers/helpers.go
package helpers
func DoHelperMethod() {
// ...
}