This will only apply to the Site that you are in. If there are other SharePoint Sites, you'll need to replicate your actions.
Click "Edit".
Click on the 3 dots next to the link
Click "Remove"
Click and hold on the 2 lines to the left of the link, and drag into the new desired posistion.
Click on the add icon at the bottom of the list.
Select from the list. A Link is for a URL, the Hub options are for internal associated Hubs, and a Label is if you want to create a group of links.
Enter the "Address"
Choose the "Display Name"
Remember to keep this concise, as a longer name may truncate on smaller screens.
Decide if you'd like this to open in a new tab or not, then press "OK".