I am trying to build custom boards using LSM9DS1, I shot through the data sheet, but the information on these two pins is not clear enough? What is the purpose of these pins(DRDY_M & DEN_A/G)?

I am designing a custom PCB using STM32F722RET6. How to connect the VREF+ pin(13) on the SMT32F722RET6?.As per the hardware development manual, it says"The VREF+ pin can be connected to the VDDA external power supply"and then, "VDDA=VDD and VSSA=VSS...