Update README

Author: FireBlade211

README.md

@@ -1,2 +1,38 @@
 # FileCmd
 A cross-platform command shell intended for file management.
+
+#  Installation
+
+<details>
+  <summary>Windows</summary>
+  Download the executable binary from the <a href="https://github.com/fireblade211/filecmd/releases">Releases</a> page and run it.
+</details>
+<details>
+  <summary>macOS</summary>
+  See the <a href="#building">Building</a> section for more info. Precompiled DMG files aren't provided for macOS (mainly because I don't own a mac lol)
+</details>
+<details>
+  <summary>Linux (Debian)</summary>
+
+  Download the <B>.DEB</B> file from the <a href="https://github.com/fireblade211/filecmd/releases">Releases</a> page, run it and click <B>Install Package</B>. You can then open the terminal and run by typing:
+  ```sh
+./FileCmd
+  ```
+  Or, to run elevated:
+  ```sh
+sudo ./FileCmd
+  ```
+</details>
+
+# Building
+Clone the repository:
+```pwsh
+git clone https://github.com/FireBlade211/FileCmd.git
+```
+Then, open the [FileCmd.slnx](src/FileCmd.slnx) file in **Visual Studio** and click the **Run** button.
+
+# Getting Started
+When **FileCmd** starts, you can type the **cmdlist** command to view a list of the commands. The command will also tell you how to access help for the other commands.
+```fcmd
+cmdlist
+```