To use a kettlebell (or two) effectively, you are going to need to get comfortable with being uncomfortable.
This means recognizing that there is a steep learning curve and settling in for a long period of time finding your "groove" with the basic techniques. Seeing that there are (at a minimum) six basic techniques with the Kettlebell, you are in for a long apprenticeship. Once you have started refining the basics on your own you are still going to need feedback on your progress and the help of someone to fine tune your technique in case you start wandering off the trail.
Now the you have a "handle" on the basics (that's a Kettlebell joke), you're going to need to start working on mastering the basics. "Mastery" is not something that happens overnight, so you can expect to spend... a lot of time working on them. The "how long" is different for every person, but I can guarantee that if you are in a hurry it will take you a long, long time.