Assign Private IP second NIC of Linux server

Information:

**KERNEL**
3.10.0-1160.80.1.el7.x86_64
**OS version**
CentOS Linux release 7.9.2009 (Core)

**Hardware Information**
CPU
Intel Xeon E3-1230v6 - 4c/8t - 3.5 GHz/3.9 GHz
RAM
32 GB ECC 2133 MHz

Data disks
2×1.2 TB SSD NVMe

Hi Everyone,
I have recently purchased an Eco Dedicated Server (So you start). I am not lying it's my first dedicated server I purchase and I am in the process to learning still. I have experienced that when I install an OS such as Linux Distribution, by default my OS is detecting to NIC (Network Interface Controller), where the following NIC are configured as follows:

1- Main NIC and fully configured by OVH: It has my public IP. I've got assign 217.xxx.xxx.xxx and additionally I purchased an IP FO and attach to the same NIC to play with 2 IP address.
2- Second NIC is not configured at all and my idea is to create an IP address such as 192.168.xxx.xxx.

So, after I follow some documentation around internet, I configured both NIC's both are UP and running, but there is a few issues, where I need to understand if the issue is about my technical knowledge and dedicated servers are not enough or simply OVH works diffently and maybe I have to touch some configuration apart of my space to work around.

I have noticed, after I configured everything I tried to ping from my IP FO to external connection such as google (8.8.8.8) doesn't ping at all or from external connection is not pinging when I attached the IP FO in the main NIC.
Second, my Private IP it is fine when I build a qemu image as they can ping each other configuring a network bridging, but when I try to ping from qemu image to external it's returning me a Destination Host Unknown. I hope any of you have been in my case and there is any solution to proper configure a virtualization infrastructure with Eco Dedicated Servers. Thanks for your help in advanced.