If the two goods are perfect complements, indifference curves are perfect right angles. Except in unusual cases, the point of optimal consumption occurs where an indifference curve is tangent to the budget constraint. The consumer re-optimizes by finding a point of tangency on the new budget constraint. A superior good is one that a consumer buys more of when his income rises. An inferior good is one that a consumer buys less of when his income rises.
All superior goods are normal, and most inferior goods are normal as well.
If you draw a curve through the points of utility maximization, you'll find the Income Expansion Path. It shows how the consumption of both goods changes in response to changes in income. If you draw a curve through these points, you'll find the Engel Curve. It shows how consumption of one good changes in response to changes in income. If the Engel Curve is upward-sloping, the good is superior.