Import Github package in go

I'm trying out AWS Lambda in go and have the following imports.

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"github.com/aws/aws-lambda-go/lambda"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/ssm"
  )

Among these I'm unable to resolve the import for package aws-sdk-go. It always suggests to create such directory in GOPATH:/src.
Here's what I have tried so far:

1. Checked GOPATH is right.
2. I also did go mod vendor which resulted in vendor directory in my project and it has aws-sdk-go under it
3. Did go get github.com/aws/aws-sdk-go and this downloaded this sdk to my GOPATH and it looks like this pkg/mod/github.com/aws/aws-sdk-go@v1.44.138/aws
4. When I try to use pkg/mod/github.com/aws/aws-sdk-go@v1.44.138/aws in my import, it complains that there cannot be @ in import.

I don't get why it doesn't refer to the package in vendor directory just like the other import github.com/aws/aws-lambda-go/lambda

Any ideas what's going on?

As indicated in the comments above, the issue was not with go code itself but the IDE.
I use IntelliJ and had GOPATH set and Module integration disabled.
To resolve the issue I removed GOPATH and enabled Module integration.

To understand Modules this blog helped me: https://go.dev/blog/using-go-modules