Update README.md

Author: mackoj

README.md

@@ -1,16 +1,40 @@
 # swift-snapshot-testing-plugin-heic
 
-# swift-snapshot-testing-plugin-heic
-
 This repo is an experimental use of this branch(https://github.com/pointfreeco/swift-snapshot-testing/pull/904) that contains a PluginAPI for `swift-snapshot-testing`.
 
 The goal of this is to show how easy it is to build a plugin.
 
 ## Usage
 
-- Add this project to dependencies inside your `Package.swift`  -> `.package(url: "https://github.com/mackoj/swift-snapshot-testing-plugin-heic.git", revision: "0.0.1"),`.
-- Then add this to your test target `.product(name: "HEICImageSerializer", package: "swift-snapshot-testing-plugin-heic"),`.
-- Then add this to the top of your test file `import HEICImageSerializer` and in the `setUp()` add this `SnapshotTesting.imageFormat = HEICImageSerializer.imageFormat`.
+To utilize the HEIC image serializer in your tests, follow these steps:
+
+1. **Add the Dependency**: Include this project as a dependency in your `Package.swift` file:
+
+    ```swift
+    .package(url: "https://github.com/mackoj/swift-snapshot-testing-plugin-heic.git", revision: "0.0.1"),
+    ```
+
+2. **Link to Your Test Target**: Add the HEICImageSerializer to your test target's dependencies:
+
+    ```swift
+    .product(name: "HEICImageSerializer", package: "swift-snapshot-testing-plugin-heic"),
+    ```
+
+3. **Import and Set Up**: In your test file, import the serializer and set the image format in the `setUp()` method:
+
+    ```swift
+    import HEICImageSerializer
+
+    override class func setUp() {
+        SnapshotTesting.imageFormat = HEICImageSerializer.imageFormat
+    }
+    ```
+
+4. **Per Assertion**: Alternatively, specify the image format for individual assertions: 
+
+    ```swift
+    assertSnapshot(of: label, as: .image(precision: 0.9, format: .heic))
+    ```
 
 ## TODO