No JTAG at all. It’s way too complicate to use it.
It depends on where you would like to boot your device.
If you would like to boot from SD card, you can simply prepared a SD card and set the boot_sel to SD device. If you would like to boot from onboard eMMC, you still need to boot from SD card first and prepared a shell script wring your binary to eMMC. That’s it!
For how to set up SD card, please see