If you are on a computer and someone 'Likes' your post or sends you a message a number appears beside the Real Gardeners Tab and a red dot beside the Bell or envelope
Go over to the Bell and click on it. You will see the notification (or a link to your message if the red dot is beside the envelope). Click on the tick to show that you have viewed your notifications.
By default you will also receive an email.
If you find the emails annoying click on the cog ...
.. be patient - sometimes I get a blank screen - but eventually there is a dropdown list as below.
Click on one or both of the ticks if you do not wish to receive notifications and/or an email.