update readme

README.md

@@ -7,8 +7,15 @@ Aegisub scripts for 3D shenanigans
 0 - Use karaOK (https://github.com/logarrhythmic/karaOK)  
 1 - Put the repo in your Aegisub/automation/include folder, under the name "kara3d".  
 2 - Create a `code once` line with the following code: `_G.require("kara3d.all")`  
-3 - Create another `code once` line with the names you will use for the classes that are now stored in `_G` (for example, `vec = _G.vector`)
+3 - Create another `code once` line with the names you will use for the classes that are now stored in `_G` (for example, `vec = _G.vector`)  
+    (alternalively, you can directly use the `_G.xxx` syntax but it's quite lengthy)
 
 ## How to Use
 
-coming soon lmao
+Build a scene tree using transforms, attach shapes to those transforms and draw them when needed with `shape:draw()`.  
+Attached shapes will follow their transform and its parents when those are modified.  
+There is no transition function yet, so you must create frame-by-frame animations.  
+
+## Note
+
+Resulting subtitle files may be really long