Importing multiple brushes in MS5/CSP:

The video's a bit slow but it is thorough, so good for beginners.
The instructions do work in Windows.
I haven't bought his brush set but it looked good so feel free to give it a try.

If you want to make your own brushes, please note that if you want your brush to repeat the colour you're painting with and not the colour the brush tip was made with then the Brush Tip needs to be created on a Grayscale/Monochrome Layer!

If you are new to MS5/CSP I highly recommend watching this short video before you begin experimenting with brushmaking:

I really wish I hadn't had to learn these basics the hard way. Just watch it.

The same user also has a longer video on brush settings in MS5:

If you're making brush tips out of scanned images and want to get rid of the white background, you can change the 'Expression color' of the layer to 'Grayscale' (or Monochrome) and click the black box next to the drop-down menu to ensure only the black is visible.
You can find your 'Expression color' drop-down box in your 'Layer Properties' window or by right-clicking your layer and selecting 'Convert Layer'.

I also find the 'Select Color Gamut' (Under 'Selection') and 'Tone Curve' (Edit>Tonal Correction>Tone Curve) options particularly useful for this process.

Remember that under 'File>Command Bar Settings' you can arrange the icons on your command bar for easy access to frequently used functions.

You can move nearly all UI elements around just by dragging and dropping, so make sure to organize them in a manner that suits your workflow. (I for one have a habit of constantly moving my 'Color Wheel' and 'Color History' around as I work.)
Note that changes to UI and brushes are saved when you close the application, so if you've made extensive changes to your UI or imported/modified brushes, it may be a good idea to make sure you close the program so the changes you've made are saved and not lost in case of power failure/software malfunction.

And yes, Manga Studio and Clip Studio Paint are indeed the same application.

To install:

Unzip the brush pack somewhere on your hard drive. Brushes are unziped .sut files. In Manga studio in the upper left corner of Sub Tool palette there is a button that opens a drop down list. In this list there is Import sub tool option. Click it and navigate to any .sut file.  Alternatively, you can just drag and drop any .sut file (or many at once) from your file browser to empty space in Sub tool palette.

> How to import brushes in CSP or MS5