Hi Everyone - so need some help/direction and hoping this is the right platform to ask this.  I have been working through the process of getting Lightning set up for my organization.  Reading tons of info and have been walking through the Readiness Report making changes and getting ready for our launch date prior to release.  I am stuck in the area of Readiness for setting up "My Domain". We currently do not have this feature enabled yet.  I have read tons of info on this and know the process of setting it up.  What I am technically struggling to understand is once I set this up and make it active for all users - how that affects users and most importantly all Installed App Packages - ie ZenDesk, etc.  I really need direction understanding what technically needs to be done to make sure if I set this up that there is no disconnect or loss of production between SFDC and our connected Apps that help run our business.  Hope that all makes sense.  Any help would be greatly appreciated! Thanks!