Connecting the Amazon echo to the SmartThings hub was relatively simple.  Just open the Alexa app on you phone, click the menu icon in the upper left corner, then Smart Home -> SmartThings.  You will then log into your smartthings account to link your account.  You can then have the Alexia app search for the new devices.  The only problem I am having right now is that my WEMO switches are showing up twice because Alexia is finding them through the SmartThings hub and directly.  I told Alexia to “Forget” the “direct linked” WEMO switches, but the next day they were there again.  I may have to investigate this further.