Hi Giovanni,
Nice scope to start with for sure.
I would say don't go to hard and start with some plossls. With your SCT the field of view will be more narrow, so a wider degree of view eyepiece would be worth getting later on.
To work out the magnfication you get the focal length of the scope and divide by the focal length of the eyepiece.
https://skyandtelescope.org/observin...pe-calculator/
Have fun.