Just connect mikromedia for XMEGA, Battery Boost shield with SHT1X PROTO temperature/humidity sensor using wire jumpers, click the microSD card in the socket and you got the hardware you need. We have created an open-source datalogger application in mikroC, mikroBasic and mikroPascal compilers for AVR and you ca freely download it from this webpage.
MikroMedia for XMEGA Bootloader
Let's make project - Datalogger for Temperature and Humidity