You can use redirects if you use content to a new url and don't want customers to see a 404 - not found page.
To create a new redirect, click on "Add Rule" on the left. A new row will appear. In the "From" field, you enter the path of the page which will be redirected. The "From" path is relative to your site, so if your domain is example.com, then the settings in the screenshot below will apply to example.com/my-old-url.
In the "To" field, you enter the destination. This is where your visitors will be sent. You can enter a relative path to stay on your domain or an absolute url such as: "https://www.test.com".
The "Status Code" lets you change between a 301 and 302 response for SEO purposes.
Once you have clicked on "Save Settings" your redirects will not become active until you publish your site again.