docs: README

README.md

@@ -1,15 +1,113 @@
 # `hcloud-upload-image`
 
-Quickly upload any raw disk images into your Hetzner Cloud projects!
+Quickly upload any raw disk images into your [Hetzner Cloud](https://hetzner.com/cloud) projects!
 
 ## About
 
+The [Hetzner Cloud API](https://docs.hetzner.cloud/) does not support uploading disk images directly, and it only
+provides a limited set of default images. The only option for custom disk images that users have is by taking a
+"snapshot" of an existing servers root disk. These can then be used to create new servers.
+
+To create a completely custom disk image, users have to follow these steps:
+
+1. Create server with the correct server type
+2. Enable rescue system for the server
+3. Boot the server
+4. Download the disk image from within the rescue system
+5. Write disk image to servers root disk
+6. Shut down the server
+7. Take a snapshot of the servers root disk
+8. Delete the server
+
+This is an annoyingly long process. Many users have automated this with [Packer](https://www.packer.io/) &
+[`packer-plugin-hcloud`](https://github.com/hetznercloud/packer-plugin-hcloud/) before, but Packer offers a lot of
+additional complexity to wrap your head around.
+
+This repository provides a simple CLI tool & Go library to do the above.
+
 ## Getting Started
 
 ### CLI
 
+#### Binary
+
+> TODO
+
+#### `go install`
+
+If you already have a recent Go toolchain installed, you can build & install the binary from source:
+
+```shell
+go install github.com/apricote/hcloud-upload-image
+```
+
+#### Usage
+
+```shell
+export HCLOUD_TOKEN="<your token>"
+hcloud-upload-image upload \
+  --image-url "https://example.com/disk-image-x86.raw.bz2" \
+  --architecture x86 \
+  --compression bz2
+```
+
+To learn more, you can use the embedded help output:
+
+```shell
+hcloud-upload-image --help
+hcloud-upload-image upload --help
+hcloud-upload-image cleanup --help
+```
+
 ### Go Library
 
+The functionality to upload images is also exposed as a library! Check out the [reference documentation](https://pkg.go.dev/github.com/apricote/hcloud-upload-image/hcloudimages).
+
+To install:
+
+```shell
+go get github.com/apricote/hcloud-upload-image
+```
+
+Example Usage:
+
+```go
+package main
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+
+	"github.com/hetznercloud/hcloud-go/v2/hcloud"
+
+	"github.com/apricote/hcloud-upload-image/hcloudimages"
+)
+
+func main() {
+	client := hcloudimages.NewClient(
+		hcloud.NewClient(hcloud.WithToken("<your token>")),
+	)
+
+	imageURL, err := url.Parse("https://example.com/disk-image-x86.raw.bz2")
+	if err != nil {
+		panic(err)
+	}
+
+	image, err := client.Upload(context.TODO(), hcloudimages.UploadOptions{
+		ImageURL:         imageURL,
+		ImageCompression: hcloudimages.CompressionBZ2,
+		Architecture:     hcloud.ArchitectureX86,
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Printf("Uploaded Image: %d", image.ID)
+}
+```
+
+
 ## Support Disclaimer
 
 This is not an official Hetzner Cloud product in any way and Hetzner Cloud does not provide support for this.