1. Hi, how do I go about signing an image for slot1 usage.

I used the following command for flashing into slot0 successfully:
    west sign -t imgtool -- --key ~/zephyrproject/bootloader/mcuboot/root-rsa-2048.pem && west flash --skip-rebuild -- --hex-file build/zephyr/zephyr.signed.hex

I adjusted my nrf52840dk_nrf52840 config as follows to flash into slot1:
    chosen {
        zephyr,code-partition = &slot1_partition;
    };

however when signing the image after this change, the offsets remain the same as it should be for slot 0
     === image configuration:
     partition offset: 49152 (0xc000)                     (slot 1 should start at 0x73000)
     partition size: 421888 (0x67000)
     rom start offset: 512 (0x200)

2. Is there any tutorials online for MCUboot usage on Zephyr?
I am attempting to get OTA firmware upgrade on my dev kit and I am not sure about the basic commands (Config Variables) to utilize mcuboot on zephyr.

Regards
Brenton