Iotawatt how to build the code

Hardware IoTaWatt
18

I am trying to compile the code in the Arduino IDE but have hit the following errors and can’t find a solution (probably because I am learning as I go and not an expert). Any help appreciated.

Thanks

"In file included from C:\Users\paulb\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.3.0\libraries\ESP8266WiFi\src/ESP8266WiFi.h:39:0,
                 from sketch\IotaWatt.h:30,
                 from sketch\GetFeedData.cpp:1:
C:\Users\paulb\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.3.0\libraries\ESP8266WiFi\src/WiFiClient.h: In instantiation of 'size_t WiFiClient::write(T&, size_t) [with T = char*; size_t = unsigned int]':
sketch\GetFeedData.cpp:288:40:   required from here
C:\Users\paulb\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.3.0\libraries\ESP8266WiFi\src/WiFiClient.h:123:36: error: request for member 'available' in 'source', which is of non-class type 'char*'
     size_t left = source.available();
                                    ^
C:\Users\paulb\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.3.0\libraries\ESP8266WiFi\src/WiFiClient.h:127:5: error: request for member 'read' in 'source', which is of non-class type 'char*'
     source.read(buffer.get(), will_send);
     ^
Multiple libraries were found for "SD.h"
 Used: C:\Users\paulb\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.3.0\libraries\SD
 Not used: C:\Program Files (x86)\Arduino\libraries\SD
exit status 1
Error compiling for board NodeMCU 1.0 (ESP-12E Module)."