If you are using a lateral flow test (LFT, Antigen) then swab your throat as well as your nose.  You don’t need to use two tests, the video is just demonstrating that you get different results from swabbing the different areas. Use a single test and swab your throat first, then your nose. #SwabYourThroat

From the UKHSA:

Thank you! This happened to me. Symptoms. Negative on nasal, positive on throat. Having this conversation on TikTok and it's clear not enough people know about this! #swabyourthroat https://t.co/l5IlQQPCgU

— Alison Hall (@AlisonReporting) January 2, 2022

UPDATE – 8th January 2022

Swabbing throat and nose ‘boosts Covid detection in lateral flow tests’

Using lateral flow tests to swab the throat and nose is more accurate than simply relying on nasal samples, senior UK health officials believe, as ministers consider updating advice for tens of millions of test users.

Telegraph.co.uk report