I recently had to replace my MacBook Air 11 (MBA). I have a Thunderbolt Display (TBD) at my office. With my old MBA, I would just plug in the power and TBD cables and hit return on the remote wireless keyboard or the wireless trackpad, and the TBD would come on (MBA lid remaining closed). It no longer does so. The only way I can get the TBD to come on is to have the MBA lid open: then the TBD will come on. If I then close the MBA lid, the TBD will remain on. HOWEVER, and this is the real problem, neither the keyboard nor the trackpad are speaking to the TBD, so I cannot do anything. How do I get these wireless devices to re-connect with the TBD, so I can work with the MBA closed?
I'm not a techie, so I need a clearly explained solution that a lay person can navigate, please.