Could you tell me how to make a Punnett square?

This site tells you exactly how it works. Check it out!

http://anthro.palomar.edu/mendel/mendel_2.htm

I am assuming that you have a simple 2 factor genetic trait. If so draw a square and divide it in each direction so that you have 4 equal boxes. Along the top write one parents genes (one letter over each box). along the left going down write the other set (again one per box. Inside the boxes, put the combination from each of the two letters. I have attached a site that gives more detail.
http://www.usoe.k12.ut.us/CURR/Science/sciber00/7th/genetics/sciber/punnett.htm

Okay I can help u we just did that make a square with 4 different section.... Get your two genotypes and put one onn each side like a graph then if you go from the side to the top write the thing you got

I usually find the most problems arise with the parentg genotypes. If a parent genotype is Tt, it will show the dominant character eg tall, but when it is involved in fertilisation it will only be able to give 1 allele (either T OR t...not both) to its offspring.  This is becasue its passed to it in either sperm/pollen or eggs, which all contain only 1 set of chromomsomes.
also note: For any gene, use only 1 letter, just use capitals for dominant alelles and little letters for reccesvie alleles eg C=curly c=straight or H=hairy h= no hair etc etc

when I draw punnet squares sometimes, I remind people that the parent's genotpyes are in sperm and eggs by drawing a circle around each letter and then add little tails to the fathers (to show its sperm and eggs).  I find this helps a bit.

So if you have a male parent with Tt and female parent Tt
you have to split up the letters (remember the letter is an allele (version of a trait) and each parent can only give you 1 allele.  The actual combination of these alleles is random and you are looking for the CHANCE that offspring will get that particualr allele combination.

 ---------- T  ---------    t                

T   -----       TT     -----      Tt

t    -----        Tt       --------    tt

Please note the punnett sqaures never come out like I write them!!!Grrrrr

Anyway the offspring have a 75% chance of being tall and a 25% chance of being short.  You have to translate the genotypes into phentypes (eg tall/short) and give either percentages or ratios (the ratio here is 3 tall: 1 short)