docs: update ISO instructions (#178)

README.md

@@ -16,10 +16,11 @@ A familiar(ish) Ubuntu desktop for Fedora Silverblue. It strives to cover these
 
 # Usage
 
-1. Download and install [test ISOs from here](https://github.com/ublue-os/bluefin/releases/tag/v1.0.0):
-   - `bluefin-38.iso` is for systems with Intel and AMD GPUs
-   - `bluefin-nvidia-38.iso` is for systems with Nvidia GPUs
-   - [Follow the installation instructions](https://ublue.it/installation/)
+1. Download and install [the ISO from here](https://ublue.it/installation/):
+   - Select "Install ublue-os/bluefin" from the menu 
+     - Choose "Install bluefin:38" if you have an AMD or Intel GPU
+     - Choose "Install bluefin-nvidia:38" if you have an Nvidia GPU
+   - [Follow the rest of the installation instructions](https://ublue.it/installation/)
 
 ### For existing Silverblue/Kinoite users