This article has been written for SharePoint modern site only and addresses the Contributors who can edit pages and add web parts to it.
To edit an existing page in SharePoint modern site, as a contributor you can access a toolbar in the top of the page content :
Once your page is in edit mode, you can see its structure (row and column) and all the web parts inside.
By hovering an area in a row/column you can add a new web part :
And select in the SharePoint web part catalog the Powell Intranet web parts :
At the moment you select the web part, a first selection (the latest created) of the ready-to-use web parts is proposed. If you click on one of them, the web part is instantly added to the page with a correct configuration displaying your content :
For example here, by clicking on the Birthday ready to use web part :
If in the latest ready-to-use web part you don't find the one perfect for you, you still can open the complete catalog by clicking on the button:
From there you will have access to the full list of "ready to use" web parts but also to the complete Powell web part catalog with a static preview of the displays.
All the web parts are categorized and sub-categorized. A search box at the top right corner allows you to quickly find what you are looking for.
You can find all the documentation related to all the web parts in this part of this help center: Webpart catalog
When you choose a web part in this catalog, it's automatically added to the page in edit mode to let you configure the required settings.
An example here after selecting the "Next badges" web part: