docs: basic usage (#140)

Fixes #136

README.md

@@ -1 +1,85 @@
-# cardano-up
+# cardano-up
+
+## Installation
+
+### Install latest release
+
+You can download the latest releases from the [Releases page](https://github.com/blinklabs-io/cardano-up/releases).
+Place the downloaded binary in `/usr/local/bin`, `~/.local/bin`, or some other convenient location and make sure
+that location has been added to your `$PATH`. 
+
+### Install from source
+
+Before starting, make sure that you have at least Go 1.21 installed locally. Run the following
+to download the latest source code and build.
+
+```
+go install github.com/blinklabs-io/cardano-up/cmd/cardano-up@main
+```
+
+Once that completes, you should have a `cardano-up` binary in `~/go/bin`.
+
+```
+$ ls -lh ~/go/bin/cardano-up
+-rwxrwxr-x 1 agaffney agaffney 16M Mar 16 08:13 /home/agaffney/go/bin/cardano-up
+```
+
+You may need to add a line like the following to your shell RC/profile to update your PATH
+to be able to find the binary.
+
+```
+export PATH=~/go/bin:$PATH
+```
+
+## Basic usage
+
+### List supported commands
+
+You can run `cardano-up` to get a list of supported commands.
+
+```
+$ cardano-up
+Usage:
+  cardano-up [command]
+
+Available Commands:
+...
+Use "cardano-up [command] --help" for more information about a command.
+```
+
+### List available packages
+
+```
+cardano-up list-available
+```
+
+### Install a package and interact with it
+
+```
+cardano-up install cardano-node
+```
+
+Add `~/.local/bin` to your `$PATH` by adding the following to your shell RC/profile to make any
+commands/scripts installed readily available
+
+```
+export PATH=~/.local/bin:$PATH
+```
+
+You can also add any env vars exported by the installed packages to your env by adding the following to your shell RC/profile:
+
+```
+eval $(cardano-up context env)
+```
+
+You should now be able to run `cardano-cli` normally.
+
+```
+cardano-cli query tip --testnet-magic 2
+```
+
+### Uninstall a package
+
+```
+cardano-up uninstall cardano-node
+```