The WordPress theme your site is built through is called Divi. The more you work with it, the more comfortable you’ll be when editing text, adding images, etc. You can access specific training videos and documentation on the different modules and options by going to Appearance > Divi Training in the left-hand toolbar.
Please note: you have been allocated the role of ‘editor’ so some things relating to the design and layout of the site can’t be changed. This is to ensure the site continues to work across all devices.
Richard at Treetop Web Studio is here to help if or when you need changes made to the website. Feel free to contact him at firstname.lastname@example.org.