Readme: add Usage section that covers the basics

.github/workflows/linux-ci.yaml

@@ -2,9 +2,7 @@ name: Linux CI
 
 on:
   push:
-    branches: [ "master" ]
-  pull_request:
-    branches: [ "master" ]
+    tags: ['v*.*.*']
 
 jobs:
   build:

.github/workflows/win-ci.yaml

@@ -2,9 +2,7 @@ name: Windows CI
 
 on:
   push:
-    branches: [ "master" ]
-  pull_request:
-    branches: [ "master" ]
+    tags: ['v*.*.*']
 
 jobs:
 

README.md

@@ -19,6 +19,16 @@ A fork of q3map2, now available as a stand-alone compiler targetting [FTEQW](htt
 - Support for entity key: _entsurfaceflags, so surfaces can override their surfaceflags
 - Support for entity key: _entcontentflags, so brushes can override their contentflags
 
+## Usage
+
+BSP: `./vmap [options] dm_foobar`  
+VIS:  `./vmap [options] -vis dm_foobar`  
+LIGHT: `./vmap [options] -light dm_foobar`
+
+You want to pass `-fs_basepath /path/to/game/root` and `-game` arguments to specify where to read textures from. If you wanted to, for example, compile a map included within Nuclide's 'base' directory you'd end up with a command-line like this:
+
+`./vmap -fs_basepath /home/user/nuclide-sdk/ -game platform -game base test_sun`
+
 ## Compiling
 To compile on a standard GNU/Linux system:
 `make`