The Target Round consists of 8 problems, dispensed only 2 at a time. You have 6 minutes to work on each pair before it's whisked away. According to the Mathcounts official website, these problems are "multi-step problems that engage Mathletes in mathematical reasoning and problem-solving processes." Calculators ARE allowed.
I honestly have very little advice about the Target Round strategy-wise. Since you only get two problems at a time, pacing is not much of an issue. Just be sure not to work on one of the problems at the exclusion of the other. Like with everything else, make sure you practice a few actual Target Rounds beforehand so that you know what to expect.