Uhh I'll try to help. A redox reaction is basically a reduction-oxidation reaction.
In a reduction reaction, electrons are being added to an element to form a negative ion. On the other hand, in an oxidation reaction, electrons are being taken away and hence forms a positive ion. The process of reduction and oxidation occur simultaneously because the electron being added in reduction actually comes from the electron being removed in oxidation. As a result of this, they are often combined using the reduction-oxidation term or simply redox reactions.
For example, in Mg+O>MgO. Mg donates two elections and hence undergoes oxidation. The oxygen recieves these two electrons and adds it onto itself, hence it undergoes reduction.
Umm... each of the process is basically described using half equations which show one part out of the two stages in a redox reaction, in other words, one half equation would show reduction whereas another would show oxidation. It's basically breaking the whole process into two separate equations.
So taking the above example of Mg+O>MgO, the oxidation process would be described using the half equation: Mg>Mg
2++2e
-. On the other hand, the reduction process would be described using the half equation: O+2e
->O
2-.
So yeah... that's kind of a little summary of it.