Thanks guys. I got it working. Both the Adafruit and Arduino tutorials were helpful.
That's what I found about zero:
There are 6 sercom channels as follows,
S0-> Configured for Serial1 (Pin 0 and 1)
S1-> Spare
S2-> Spare
S3-> Default I2C ports
S4-> Default SPI (SPI/ICSP Header)
S5-> Configured for Serial (Debug port)
I used Sercom1 to create additional Wire and it worked on pin 35 and 37 but not on 11 and 13. I also tried Sercom2 on pins 3 and 4 but it didn't work. Any ideas?