Rewrite installation section of README

Author: spalmurray

README.md

@@ -14,9 +14,32 @@ The Sentry Prevent CLI is responsible for uploading code coverage and test resul
 
 # Installing
 
-As of today, you are not able to install the Sentry Prevent CLI. We are planning to release it on the PyPI and for direct download in the near future.
-
-If you're determined, you can build the CLI yourself from source by running `uv build` in the `prevent-cli` directory.
+### PyPI
+
+```
+pip install sentry-prevent-cli
+```
+
+### Binary
+
+We build and publish binaries for Linux, MacOS, and Windows. See our GitHub Releases for the full list of OS/architecture combos we build for. We'll use our macos binary for demonstration purposes here:
+```
+curl -o sentry-prevent-cli -L "https://github.com/getsentry/prevent-cli/releases/latest/download/sentry-prevent-cli_macos"
+chmod +x sentry-prevent-cli
+```
+
+#### Verifying the binary
+If you'd like, you may use Sigstore's Cosign to verify the integrity of your download against our provided Cosign bundles and identity details. For more information on Cosign along with installation instructions, see their [documentation](https://docs.sigstore.dev/cosign/system_config/installation).
+
+First get the appropriate Cosign bundle from our GitHub Release assets. Appending `.bundle` to the binary URL will get you the right file.
+```
+curl -O -L "https://github.com/getsentry/prevent-cli/releases/latest/download/sentry-prevent-cli_macos.bundle"
+```
+Then, use `cosign` to verify the binary:
+```
+cosign verify-blob sentry-prevent-cli --bundle sentry-prevent-cli_macos.bundle --certificate-identity-regexp=^https://github.com/getsentry/prevent-cli --certificate-oidc-issuer=https://token.actions.githubusercontent.com
+```
+The OIDC identity here is associated with the specific workflow run that signs the binary. If this command says the binary is verified, you can trust you've recieved the same binary we built in our GitHub Actions workflow.
 
 # Usage