Write the alleles for one parent across the top of the square
Write the alleles for the other parent along the side of the square
Draw a box with enough sections for all possible allele combinations
Fill in each box by combining the top allele with the side allele
Use the completed boxes to find the possible genotypes of the offspring
Count the boxes to find the genotype ratios
Convert genotypes to phenotypes if needed
Use the results to determine the probability of each trait