How to open and edit a document in SharePoint

i) Navigate to the correct library and file

ii) Click once on the file name and it will open

iii) Office files will open a preview in your browser by default

iv) You can choose to edit in your browser (normally for minor changes) or in the full Office software on your laptop

v) Make and save your changes as normal

NB - Editing in a Browser gives you a limited set of ribbon commands. To be able to use the full ribbons always edit in the native application such as Word or Excel.