Update README

Author: ThatOneShortGuy

README.md

@@ -1,11 +1,31 @@
 # Mindustry Assembler
-The assembler doesn't do much other that make the jump commands dynamically calculated. It is meant for use with the [Mindustry Compiler]().
+The assembler doesn't do much other that make the jump commands dynamically calculated. It is meant for use with the [Mindustry Compiler](TBD).
 
 ## Usage
+Almost like normal Mindustry code, but with a few differences:
+1. All code points must have whitespace in front of them after the newline
+```mindustry
+# Comments are fine
+        jump 21 always x false # They can be at the end of a line
+        op add x x 1
+```
+2. There are labels. They start with an &. They are used to calculate the location of a line. They do not need to be followed by an instruction, but they can be.
+```mindustry
+        set i 0
+# &loop will be computed correctly even when there are comments
+&loop   print "Hello, World!" # Here's a comment that doesn't matter
+# Oh look, another comment
+        printflush message1
+        op add i i 1
+        jump &loop lessThan i 10
+```
+`&loop` will be computed and replaced in the jump command with the line number of the `&loop` label (1).
+
+### Running the assembler
 ```sh
 assembler [-d] [-h] [-c] <file> [-o <output_file>]
 ```
-- `-d`: Create a debug file
+- `-d`: Create a debug file (shows the line numbers of each label). The file is named `<file>.sym`
 - `-h`: Print this help message
 - `-c`: Copy the output to the clipboard
 - `file`: The file to assemble