Revise instructions for new Tails Greeter

wiki/src/doc/first_steps/startup_options/mac_spoofing.mdwn

@@ -108,13 +108,13 @@ Disable MAC address spoofing
 You can disable MAC address spoofing from [[<span class="application">Tails
 Greeter</span>|startup_options#tails_greeter]]:
 
-1. When <span class="application">Tails Greeter</span> appears, in the
-   <span class="guilabel">Welcome to Tails</span> window, click on the
-   <span class="button">Yes</span> button. Then click on the
-   <span class="button">Forward</span> button.
+1. When <span class="application">Tails Greeter</span> appears, click on the
+   <span class="button">[[!img lib/list-add.png alt="Expand" class="symbolic" link="no"]]</span> button.
 
-2. In the <span class="guilabel">MAC address spoofing</span> section, deselect
-   the <span class="guilabel">Spoof all MAC addresses</span> option.
+2. When the <span class="guilabel">Additional Settings</span> dialog appears,
+   click on <span class="guilabel">MAC Address Spoofing</span>.
+
+3. Select the <span class="guilabel">Don't spoof MAC addresses</span> option.
 
 Other considerations
 ====================