Adding (Multiple) Widgets
You can only add one widget above or below the clock (To add one, long-press Niagara's agenda widget/clock at the top and tap on Add custom widget). However, with Niagara Pro, Niagara Launcher also lets you attach widgets to pop-ups. Each app can have a pop-up and you can also attach two pop-ups to the Niagara button. See this article on how to create pop-ups. After creating a pop-up, open and long-press on it and select Edit [App/Folder] pop-up. Then, either suggested widgets will appear at the top of the selection list or you have to scroll all the way down and tap on Select a widget.
What about a widget page?
We are not fans of widget pages. The only thing widgets have in common there is, well, they’re all widgets. So why should they be grouped? Showing a weather widget below the clock and accessing your calendar agenda via a swipe / by tapping on a button makes more sense. Also, widgets often tend to use much memory. The concept of a widget list would kind of endorse users to cluster the page full of widgets. In contrast to that, a pop-up shows only a single widget at once, so not every widget has to be loaded into ram when you want to access one.