What to do with objects I have found
Contact the Portable Antiquities Scheme (PAS). Their Finds Liaison Officers (FLO) are fantastic at helping identify finds discovered by metal detectorists, walkers, etc and they have a huge amount of knowledge. They will also be able to record your find and add it to the archaeological record.
To get in touch with your local FLO click on this link: https://finds.org.uk/contacts
You can also search through their database https://finds.org.uk/database to see if you can find anything similar to your own discovery.
What to do if I have found an area or site that may be of interest
Contact your local Historic Environment Record (HER) Office to speak to an archaeologist there. They will be able to not only look at what you have discovered but also, if necessary, add it to the archaeological record.
If it is a site that has already been recorded you may like to look at the Heritage Gateway and the Archaeology Data Service (ADS) websites where you can search for sites by type and location.