How to setup debug environment for image running in target board? #toolchain #yocto


I'm working with NXP iMX8QXPMEK evaluation board.  I downloaded bsp release L4.19.35_1.1.0_MX8QXP from following site:
This bsp release is for Yocto Project 2.7 (Warrior)
I built yocto project for this bsp release.  I copied built image into sd card and then booted NXP board from sd card.  I need to step through USB Host Subsystem source code running in embedded linux kernel? 
There is a serial connection between my NXP evaluation board and my PC.  Micro-USB Debug port in NXP board is connected to USB port in my PC.  How do I setup debugging environment so I can see source code and symbols running in my NXP board?