First and foremost please tell me you are connecting the first one to the router via ethernet and not trying to go via wireless.
Router---(ethernet)---ENS202---(Wifi)---ENS202--(ethernet)---access point--(wifi)--devices will give you full speed
Router ---(Wifi)---ENS202 ---(Wifi)---ENS202--(wifi)--devices will give you 1/4 speed to SHARE among all devices in building 2.
The reason for this is each time a single radio acts as a repeater you cut the bandwidth in half because it is now playing a middle man. In the second configuration each ENS202 is acting as a repeater and thus each time it gets cut in half. So if you start with a solid 100mbps connection from the router to 1st ENS202, you end up with 25mbps shared by all devices in building 2.
Let me break down the difference between devices. Many commercial access points/bridges will easily swap between one function or the other.
Access Point: ethernet in---wifi and ethernet out
Bridge: wifi in----ethernet out (or ethernet and wifi out)
Repeater: wifi in----wifi out
All of these devices should be on the same subnet. So if primary router is 192.168.0.1 then these should also be at 192.168.0.x.
Go into primary router and make sure DHCP does not start until at least .10. If it does start at .2 then change it to go from .100-.254, reboot router and any device currently connected to it.
I would just go ahead and do a factory reset on the ENS202 devices. Then you will need to manually set your IP address on the computer you want to use to configure them, plug cable direct from PC to the device and then input the default IP and then set it up accordingly and change its IP to be .02 for 1st ENS202, .03 for 2nd ENS202, and .04 for the other router/access point in building 2.
So the 1st ENS202 under configuration 1 above will be an access point, then the 2nd ENS202 will be a wireless bridge.