Tip: Rename Files Sequentially on Windows or Mac
In File Explorer select all the files you want to rename and right-click on the first one in the list, choose Rename from the menu, and type in the name. This will automatically change all the other files with the same root name with a suffix: (1), (2), and so on.
Select the files you want to rename, right-click (or hold down the Control key and click) the group, and choose Rename [Number] Items from the contextual menu. Supply a keyword, and the Mac will rename the files and tack on a number in a sequence.