I haven't learned half reactions for oxidation and reduction so please teach me by leading me from step to step....

I don't get this..

Sn2+ +2Fe3+---> Sn4+ +2Fe2+

The answer key says
Oxidation: Sn2+--->Sn4+ +2e-
Reduction: 2Fe3+ + 2e----->2Fe2+

I think I answered this elsewhere.