Update info on enabling Data Streamer (#4)

* Update info on enabling Data Streamer

* Fix 'click here' link

* Do some edits

README.md

@@ -1,36 +1,39 @@
 # Hacking STEM [![Build Status](https://travis-ci.org/Microsoft/pxt-hacking-stem.svg?branch=master)](https://travis-ci.org/Microsoft/pxt-hacking-stem)
 
-Support for [Hacking STEM](https://www.microsoft.com/en-us/education/education-workshop/activity-library.aspx) activities in [micro:bit](https://makecode.microbit.org). For Hacking Stem activities you will need excel add-on Data Streamer as well. To download Data Streamer [click here](https://www.microsoft.com/en-us/download/details.aspx?id=56976). This extension helps build the code for emitting serial data in the format required by Data Streamer excel addon. 
+Support for [Hacking STEM](https://www.microsoft.com/en-us/education/education-workshop/activity-library.aspx) activities in [micro:bit](https://makecode.microbit.org). For Hacking Stem activities you will need to enable the Data Streamer Add-in in Excel. For information on enabling Data Streamer, [click here](https://aka.ms/data-streamer). This extension helps build the code to emit serial data in the format required by Data Streamer.
 
 ## Usage
 
-Go to https://makecode.microbit.org, click on the gearwheel menu and select ``Extensions``, search for ``hacking stem`` and select this extension. Once you load the extension you should see a new category named DataStreamer. Hacking Stem extension sets the baud rate of serial output to 9600 as required by data streamer add-on in excel.
+Go to https://makecode.microbit.org, click on the gearwheel menu and select ``Extensions``, search for ``hacking stem`` and select this extension. Once you load the extension you should see a new category named **DataStreamer**. THe Hacking Stem extension sets the baud rate for the serial output to 9600 as required by data streamer add-on in excel.
 
 Following are the API reference:
 
 ## writeNumber
+
 The ``||dataStreamer.writeNumber||`` block writes a number to the serial port as a floating point number.
 
 ```sig
 dataStreamer.writeNumber(1.52, 2);
 ```
 
 ### Parameters
+
 * `value` is the floating point number to write to the serial port
 * `decimal digits` is the number of decimal digits to write. Default is 2.
 
 ### Example 1
-For example,
+
+A simple write number.
 
 ```blocks
 dataStreamer.writeNumber(1.52);
 ```
 
-writes the following number to serial
-1.52
+writes the number `1.52` to serial.
 
 ### Example 2
-This example reads the analog signal on pin ``P0``, scales it to 3.3v and writes it to serial with 4 decimal digits precision.
+
+This example reads the analog signal on pin ``P0``, scales it to 3.3v and writes it to serial as decimal with 4 digit precision.
 
 ```blocks
 let mv = 0
@@ -41,13 +44,15 @@ basic.forever(() => {
 ```
 
 ## writeLine
+
 The ``||dataStreamer.writeString||`` block writes a new line to the serial port.
 
 ```sig
 dataStreamer.writeLine();
 ```
 
 ### Example: Writing values in a loop
+
 This program writes a series of accererlation values to the serial port repeatedly. 
 
 ```blocks
@@ -58,6 +63,7 @@ basic.forever(function () {
 ```
 
 ## writeString
+
 The ``||dataStreamer.writeString||`` block writes a string to the serial port, without starting a new line afterward.
 
 ```sig
@@ -68,7 +74,8 @@ dataStreamer.writeString(",");
 * `text` is the string to write to the serial port
 
 ### Example: Writing comma seperated values in a loop
-This program writes a comma `,` seperated x,y,z acceleration values to the serial port repeatedly..
+
+This program writes a comma `,` seperated x,y,z acceleration values to the serial port repeatedly.
 
 ```blocks
 basic.forever(function () {
@@ -82,16 +89,19 @@ basic.forever(function () {
 ```
 
 ## writeNumberArray
-The ``||dataStreamer.writeNumberArray||`` block writes a array of numbers to the serial port as a comma seperated values, without starting a new line afterward.
+
+The ``||dataStreamer.writeNumberArray||`` block writes an array of numbers to the serial port as a comma seperated values, without starting a new line afterward.
 
 ```sig
 dataStreamer.writeNumberArray([0,1,2]);
 ```
 
 ### Parameters
+
 * `text` is the string to write to the serial port
 
 ### Example: Writing comma seperated values in a loop
+
 This program writes a comma `,` seperated x,y,z acceleration values to the serial port repeatedly. 
 
 ```blocks
@@ -106,13 +116,15 @@ basic.forever(function () {
 ```
 
 ## setBaudRate
-The ``||dataStreamer.setBaudRate||`` sets the baud rate. Default is 9600 for datastreamer
+
+The ``||dataStreamer.setBaudRate||`` sets the baud rate. Default is 9600 (this is the baud rate used by Excel Data Streamer).
 
 ```sig
 dataStreamer.setBaudRate(9600);
 ```
 
 ### Parameters
+
 * `rate` is the number for the baud rate
 
 ## License