Hi Oleg7
Best way to try the use of VSTs with your Yamaha is to download some free ones (or trial versions from the larger manufactures) and then load them on to your computer, and connect your Yamaha to the computer, and just see how it goes.
As to learning how to use them, then a Wersi keyboard and VSTs is quite straight forward, an Arranger and computer however is a very steep learning curve, while the Receptor is midway between the 2.
Hope this helps

Bill