Doc `0Dxx` better, add tutorial link.

...because I can never seem to do one thing at a time?

doc/1-intro/README.md

@@ -20,4 +20,10 @@ it also has a flexible windowing system which you may move around and organize.
 
 see [2-interface](../2-interface/README.md) and [3-pattern](../3-pattern/README.md) for more information.
 
-once familiar with the tracker, look to [9-guides](../9-guides/README.md) for useful techniques.
+once familiar with the tracker, look to [9-guides](../9-guides/README.md) for useful techniques.
+
+
+
+# links
+
+[Furnace Tutorials](https://youtube.com/playlist?list=PLCELB6AsTZUnwv0PC5AAGHjvg47F44YQ1): video tutorials created by Spinning Square Waves.

doc/3-pattern/effects.md

@@ -71,8 +71,8 @@ not all chips support these effects.
 
 - `0Bxx`: **Jump to order.** `x` is the order to play after the current row.
   - this marks the end of a loop with order `x` as the loop start.
-- `0Dxx`: **Jump to next pattern.** skips the current row and remainder of current order.
-  - this can be used to shorten the current order.
+- `0Dxx`: **Jump to next pattern.** skips the current row and remainder of current order. `x` is the row at which to start playing the next pattern.
+  - this can be used to shorten the current order as though it had a different pattern length.
 - `FFxx`: **Stop song.** stops playback and ends the song. `x` is ignored.
 
 ## note