Can you explain to me HOW to do this question (have an exam)?

You have crossed two maize plants that are both heterozygous for a gene controlling kernel colour and for a gene controlling kernel shape. uming that allele C (brown kernels) is dominant over c (yellow kernels), and that R (round kernels) is dominant over r (wrinkled kernels), describe the genotypes and phenotypes of the progeny of this cross, and explain what the likely ratio of phenotypes would be.