Google provides a number of templates that you can use to form the basis of your slide presentations. You can create a new presentation based on a template, then edit the slides as required.
To create a slide presentation based on a template:
From the Google Drive screen, click on the New button.
Choose Google Slides, then From a Template
From an existing presentation, click on the File menu, choose New, then From template
Choose the General tab for standard Google templates, or your domain tab for custom templates for your organisation. Click on the template you wish to use to create a new presentation based on that template.
Once the new presentation has been created, you can name the presentation by double-clicking on the presentation name and typing a new name.