Explain plugins (#786)

* explain how to use plugins in c-lightning

* try a simpler explanation for activating plugins

* c-lightning -> lightningd

* try a note box

* edits

* edit

* fix commas

05_node_operations.asciidoc

@@ -810,7 +810,19 @@ With the wider adoption of multipath payments, smaller channels are less of a bu
 The +c-lightning+ plugin works very differently in comparison to the +lnd+ autopilot.
 First, it differs in the algorithms used to make the recommendations. We will not cover this here. Secondly, it differs in its user interface.
 You will need to download the _autopilot plugin_ from the +c-lightning+ plugin repository at https://github.com/lightningd/plugins/tree/master/autopilot and activate it.
-We have already explained how to activate plugins in +c-lightning+.
+
+[NOTE]
+====
+In order to activate a plugin in +c-lightning+, place it into the +~/.lightning/plugins+ directory, ensure that it's executable (e.g. +chmod +x ~/.lightning/plugins/autopilot.py+), then restart +lightningd+.
+
+Alternatively, if you don't want a plugin to automatically activate when you start +lightningd+ you can place it in a different directory and manually activate it with the +plugin+ argument to +lightningd+:
+
+----
+   lightningd --plugin=~/lightning-plugins/autopilot.py
+----
+
+====
+
 The autopilot in +c-lightning+ is controlled via 3 configuration values which can be set in the config file or as command line arguments when you start +lightningd+.
 
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