Help with Hive install replacing Honeywell t3 wired thermostats on combi

Hi Guys,

I have a new build, with a combi boiler (Vaillant Ecofit Sustain).

There are two thermostats (honeywell T3 Wired), one upstairs one downstairs. Attached is a picture of the wiring of the one downstairs and a picture of the wiring diagram from the Hive. Can anyone guide me as to which wires go where into the hive please? I understand the Live and Neutral but not how the switch part works.

thanks in advance!

https://preview.redd.it/2gxlc57h6f0g1.jpg?width=2252&format=pjpg&auto=webp&s=9410c2b5f35467b97a72b11a8090e772eebea150

https://preview.redd.it/obkgfzkh6f0g1.jpg?width=2252&format=pjpg&auto=webp&s=9a5dd61fa476a2dc99353991b3f6ec102c27cd33