diff --git a/src/main/scala/net/kemitix/s3thorp/Sync.scala b/src/main/scala/net/kemitix/s3thorp/Sync.scala
index 4d604c7..ee29d1f 100644
--- a/src/main/scala/net/kemitix/s3thorp/Sync.scala
+++ b/src/main/scala/net/kemitix/s3thorp/Sync.scala
@@ -2,21 +2,21 @@ package net.kemitix.s3thorp
 
 import java.nio.file.{DirectoryStream, Files, Path, Paths}
 
-import scala.collection.JavaConverters._
-import fs2.Stream
 import cats.effect._
-import Main.putStrLn
+import fs2.Stream
+import net.kemitix.s3thorp.Main.putStrLn
+
+import scala.collection.JavaConverters._
+import scala.concurrent.Promise
 
 object Sync {
   def apply(c: Config): IO[Unit] = for {
     _ <- putStrLn(s"Bucket: ${c.bucket}, Prefix: ${c.prefix}, Source: ${c.source}")
     _ <- {
-
-      // a stream of files in the source directory
-      val pathStream: Stream[IO, Path] = streamDirectoryPaths(Paths.get(c.source))
-
-
-      IO.unit
+      streamDirectoryPaths(Paths.get(c.source)).flatMap(
+        enrichWithS3MetaData).flatMap(
+        uploadRequiredFilter).flatMap(
+        performUpload).compile.drain
     }
   } yield ()
 
@@ -43,4 +43,23 @@ object Sync {
       flatMap(openDirectory).
       flatMap(recurseIntoSubDirectories)
   }
+
+  case class S3MetaData()
+
+  private def enrichWithS3MetaData: Path => Stream[IO, S3MetaData] = path => {
+    // HEAD(bucket, prefix, relative(path))
+    // create blank S3MetaData records (sealed trait?)
+    }
+
+  private def uploadRequiredFilter: S3MetaData => Stream[IO, Path] =
+    s3Metadata => {
+      //md5File(localFile)
+      //filter(localHash => options.force || localHash != metadataHash)
+    }
+
+  private def performUpload: Path => Stream[IO, Promise[Unit]] =
+    path => {
+      // upload
+      IO.unit
+    }
 }