Adding an AP One Access Point to an existing LAN

I have a customer that has another manufacturer wireless router (which is maintained by his own IT person but shared the admin password with me). Router is in the office and there is almost no WiFi outside this office.
I would like to recommend adding AP One and need to test it’s effectiveness first.
What router settings I need to change for the test? - I don’t want to impact his existing setup but can effort a short wireless down

Any other suggestions?

Thanks,

Hi Moshe,

On top of my head we could have the AP One in bridge mode, with auto channel selection or manually selecting a different non-overlapping channel, broadcasting a different SSID, and connect the AP One to the same LAN by an Ethenet cable side-by-side with their existing AP and check for signal and throughput for these two different SSIDs / equipments at different spots and distances.

Thanks,
Kurt