192.168.10.101/24 is the host computers IP address range for connection to you local network,
probably assigned via DHCP.
The FPGA card cannot share this range and must have an independent connection and IP address range. That is, you cannot share the real time LinuxCNC Ethernet connection with general internet connections so if you want internet connectivity you must have 2 network interfaces on the host.
This can be done in a variety of ways. Some Motherboards have 2 Ethernet connections, an additional PCI/PCIE Ethernet card can be installed, a USB-->Ethernet dongle, a USB-WIFI adapter etc etc.
Once this is done you need to setup one network interface for internet access (this should normally be the USB/external card) and the other (usually motherboard) interface for connecting to the FPGA card
I would suggest using the FPGA cards 10.10.10.10 address rather than 192.168.1.121 as its less likely to overlap with common DHCP assigned NAT address ranges
There is a bit of information about manual network setup in the hm2_eth manual page. Note that this is not really linuxCNC related but just standard Linux network setup, I typically just set up the interfaces with the network manager GUI
