Construct an Equation for this reaction

Create the two half equations. Multiply each one (as required) to balance the electrons. Combine and simplify.

I don't know how to create the two half equations?

I can do the rest of the steps except make them.

Get 2 equations. Question tells you Sn2+ goes to Sn4+ so
eqn 1- Sn2+ --->Sn4+ +2e-

Question also tells you that it forms I2 so
eqn 2- 2IO3- + 12H+ + 10e- ----> I2 +6H2O
You balance the equation as normal and you have to balance the charges using electrons.

eqn1 *5 to cancel electrons when combining equations
5Sn2+ ---> 5Sn4+ +10e-
combine equations and you get
5Sn2+ +2IO3- +12H+ ----> Sn4+ + I2 +6H2O