If you have had both Vaccines, you would not need to isolate and will follow the rules as if you were returning from a Green Country.
If you have not had a double vaccine, you will need to quarantine for a period of 10 days and take a pre-departure test, and a PCR test on day 2 and day 8 with the option for 'Test to Release' on day 5 to end self-isolation early.
Arrivals traveling from 'amber list' countries will be required to book test packages before traveling from one of the government's approved list of providers.
Length of quarantine:
10 Days if not vaccinated
No Quarantine if Fully Vaccinated more than 14 days before travel
More information can be found here
The Amber list
Updated 19th July 2021
All other countries that are not listed on the Green or Red list are on the Amber list.
*Amber plus list, people returning must follow the old Amber rules and quarantine at home for 10 days and take a test on day 2 and day 8. You can opt to test to release on day 5, but you must still take the day 8 test.