Use the specific heat equation for each one:
Q = mCT
m is mass
T is change in temp
C is spec heat
You will not only have to calculate three different specific heats, but also do the heat of vaporization and heat of fusion.
Heat of vaporization is 3.33 * 10^5 J/Kg
Heat of Fusion is 2.26 * 10^6 J/Kg
You’ll want to make sure all your units match. So change all Kg to g (or g to Kg)
-20 to 0 = mC(Ice)T
Melt ice (fusion) = m(heat of fusion)
0 to 100 = mC(Water)T
Boil (Vaporization) = m(heat of vaporization)
100 to 250 = mC(Steam)T
Then add each one together