How to set credentials in AWS SDK v3 JavaScript?

I am scouring the documentation, and it only provides pseudo-code of the credentials for v3 (e.g. const client = new S3Client(clientParams)

How do I initialize an S3Client with the bucket and credentials to perform a getSignedUrl request? Any resources pointing me in the right direction would be most helpful. I've even searched YouTube, SO, etc and I can't find any specific info on v3. Even the documentation and examples doesn't provide the actual code to use credentials. Thanks!

As an aside, do I have to include the fake folder structure in the filename, or can I just use the actual filename? For example: bucket/folder1/folder2/uniqueFilename.zip or uniqueFilename.zip

Here's the code I have so far: (Keep in mind I was returning the wasabiObjKey to ensure I was getting the correct file name. I am. It's the client, GetObjectCommand, and getSignedUrl that I'm having issues with.

exports.getPresignedUrl = functions.https.onCall(async (data, ctx) => {
  const wasabiObjKey = `${data.bucket_prefix ? `${data.bucket_prefix}/` : ''}${data.uid.replace(/-/g, '_').toLowerCase()}${data.variation ? `_${data.variation.replace(/\./g, '').toLowerCase()}` : ''}.zip`
  const { S3Client, GetObjectCommand } = require('@aws-sdk/client-s3')
  const s3 = new S3Client({
    bucketEndpoint: functions.config().s3_bucket.name,
    region: functions.config().s3_bucket.region,
    credentials: {
      secretAccessKey: functions.config().s3.secret,
      accessKeyId: functions.config().s3.access_key
    }
  })
  const command = new GetObjectCommand({
    Bucket: functions.config().s3_bucket.name,
    Key: wasabiObjKey,
  })
  const { getSignedUrl } = require("@aws-sdk/s3-request-presigner")
  const url = getSignedUrl(s3, command, { expiresIn: 60 })
  return wasabiObjKey
})