Ok so i tried adding this to the header code and I am getting the following errors after trying to compile it.
c:/users/aditya/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32dev\src\main.cpp.o:(.literal._Z5setupv+0x8): undefined reference to `DS3231::begin()'
c:/users/aditya/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32dev\src\main.cpp.o: in function `setup()':
C:\Users\Aditya\Documents\PlatformIO\Projects\Set_time_ds3231/src/main.cpp:31: undefined reference to `DS3231::begin()'
c:/users/aditya/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32dev\liba69\libDS3231.a(DS3231.cpp.o):(.literal._ZN6DS32317setTimeEhhh+0x0): undefined reference to `DS3231::_writeRegister(unsigned char, unsigned char)'
c:/users/aditya/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32dev\liba69\libDS3231.a(DS3231.cpp.o):(.literal._ZN6DS32317getTimeEv+0x0): undefined reference to `DS3231::_burstRead()'
c:/users/aditya/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32dev\liba69\libDS3231.a(DS3231.cpp.o): in function `DS3231::setTime(unsigned char, unsigned char, unsigned char)':
C:\Users\Aditya\Documents\PlatformIO\Projects\Set_time_ds3231/lib/DS3231/DS3231.cpp:89: undefined reference to `DS3231::_writeRegister(unsigned char, unsigned char)'
c:/users/aditya/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: C:\Users\Aditya\Documents\PlatformIO\Projects\Set_time_ds3231/lib/DS3231/DS3231.cpp:90: undefined reference to `DS3231::_writeRegister(unsigned char, unsigned char)'
c:/users/aditya/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: C:\Users\Aditya\Documents\PlatformIO\Projects\Set_time_ds3231/lib/DS3231/DS3231.cpp:91: undefined reference to `DS3231::_writeRegister(unsigned char, unsigned char)'
c:/users/aditya/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32dev\liba69\libDS3231.a(DS3231.cpp.o): in function `DS3231::getTime()':
C:\Users\Aditya\Documents\PlatformIO\Projects\Set_time_ds3231/lib/DS3231/DS3231.cpp:74: undefined reference to `DS3231::_burstRead()'
collect2.exe: error: ld returned 1 exit status
*** [.pio\build\esp32dev\firmware.elf] Error 1