Buildroot first steps after flashing my SD-Card

The beginner with Buildroot that I am, has freshly flashed his STM32MP157C-DK2 SD-Card with it’s corresponding Buildroot image :

Linux buildroot 4.19.26 #1 SMP PREEMPT Tue Oct 20 16:10:37 CEST 2020 armv7l GNU/Linux

My problem is that the MPU does not respond to any command. I am only used to Ubuntu and debian where installing packages is really easy compared to Buildroot. I am new to Buildroot and I don’t know how to use it. ifconfig gives me:

lo        Link encap:Local Loopback
          inet addr:  Mask:
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

So to summarize:

1- I would be interested in knowing the first steps t do after flashing the SD-Card (Installation of Packages etc… )

2- How do I configure my Ethernet connection.

Technically, buildroot doesn’t have an official package manager… There are ‘addon’ packages todo something, but with buildroot you define your complete system thru their config layers…

You can try defining BR2_SYSTEM_DHCP or just setup /etc/network/interfaces