No landline connection since upgrade to eero

[AnnieLou]

I have query re how to get a connected landline since my upgrade to eero several months ago. There were no spare connection points in my eero box as the 3 are taken up with a cable to a box labelled 'openreach', a power cable and cable to my talk talk box.
I do have a device with 'grandstream' written on it. It has a blue cable, a power cable and a white cable that looks like I'd plug my landline into. However I've no idea where or how I would connect this. Any help gratefully received- the less technical and jargon filled the better!!
Also how do I get a longer cable from my openreach box to my eero to allow me to move the eero higher than 50cm??

[KeithFrench]

You can buy Ethernet cables from most of the usual places. I would go for what is called Cat 6 cables to increase the length of the cable from the Openreach box (called an ONT) to your Eero. The Ethernet cable from the Grandstream connects to the other Ethernet port of the Eero. If you find you need more Ethernet ports on the Eero, you can always buy a Gigabit Ethernet switch (often in 5 or 8-port variants).