For part A. First you can order the terms according to those that have the same literal part, like this
First those who have a^2 then those who have a, then those who have b^2, then those who have b and finally, those who have no literal part
Now you can add those that have the same literal part
For part B. First make the product and then add those that have the same literal part
So, for the point 1)
for the point 2)
for the point 3)
Finally, for the point 4)