*Punnet Squares

Hi, i know that this a math forum, and my question is a biology 30 question. But punnet squares, are punnet squares.

I know how to make a punnet square for monohybrids, but not dihybrids or anything bigger. I also dont know how to answer any punnet squares.
If i had to answer it with genotype, phenotype, and the phenontypic ratio; how would i do it?
If someone could please help that would be great!,
Thx horses7

Example Question:

In guinea pigs, black hair color (B) is dominant to brown hair color (b). Long hair (L) is dominant to short hair (l). What are the phenotypes of the parents in the cross BbLi x BbLL? Consruct a punnet square for the offspring of the cross.

Well you know that each gamete from the parents will have one of each allele - the hair colour and the length of the hair - giving us 4 combinations for each sperm and egg: BL, Bl, bL, bl (assuming they're present in equal amounts).

So construct your punnet square with the above combinations labelled on the sides and match them up.

The each row/column of gametes are representative of one sperm and the other one egg.