XS++ 3.1 Guide-Flashing, Customizing, Recovering

[naxself]

naxself: Ans1> Yes, You Have A Perfect Pack For Flashing Your Phone.
Ans2> Yes, You May Add Languages Without Flashing Your Phone.

Thanks! Next question: how do I add languages without flashing? (I'm sure that's a dumb question, but I haven't been able to find a guide that I understand.)

EDIT: Couple more questions:
1. Can I use the SE Update Service to recover from a bad flash?
2. When flashing, how long do I need to hold the "C" button down?

Again, apologies for the silly questions...