Regarding customising the OpenWrt firmware

i am using yuncore AX820 with soc MediaTek MT7621AT ver 1, eco 3 and wlan hardware MediaTek MT7621DAT, MediaTek MT7905N, MediaTek MT7975DN i have installed the openwrt firmware in this router and can able to setup the acess points now i want to

  1. change the ui interface like adding logo etc
  2. adding uart service
  3. adding mqtt service

is there any way to doing all using ssh cmd prmpt or do i have the change the firmware by build one in my owm if so can someone tell me how can i do that?

if someone have schematic of my board that also will be helpful

thanks and regards

can anyone respond for this topic??

Change the css style sheets in /www/luci-static/bootstrap/

And you can edit the nav menu in /usr/share/luci/menu.d/