How to define user block to store user data in RCM 3000

I need to write some data using writeUserBlock() function in RCM 3000. But how can I choose an address offset in user block to write something there. Can I take 0 as address like writeUserBlock(0,data,sizeof(data)) . Please help.

Take a look at the userblock_sample.c application.

/* Save the data to the user block */
save_data[0] = &test_data;
save_lens[0] = sizeof(test_data);
save_data[1] = &test_long;
save_lens[1] = sizeof(test_long);
save_data[2] = test_string;
save_lens[2] = TEST_STRING_LEN;
writeUserBlockArray(0, save_data, save_lens, 3);