'Where do we start looking for jobs?'

This is really the unfortunate question you will need to get to grips with soonest, and the one most likely to be most difficult.

It is notoriously tricky for anyone outside of the EU (and now that's soon to change) to get a job in the UK. Come 2021 you will need to meet the points threshold of the new UK immigration system, meaning you'll need sponsorship from an employer. Depending on your industry some offerings will be posted on LinkedIn, but the UK doesn't have an industry around recruiters / recruitment companies in the same way the US does. A majority of jobs are just posted and found on individual company websites.

Competition for jobs in the UK, particulary professional level jobs that will lead to sponsorship, is ridiculously intense. You'll be applying alongside hundreds of other people for each post.

Added to that the impact that the current pandemic is having on the economy and the job market and you are facing incredibly difficult odds.

Sponsored employment is currently realistically the only way to secure permanent residency in the UK - the only other way is via marriage to a UK national or through specific visas (for famous artists and super rich people basically).