Question

How does your body know how to put the amino acids together in order to make a protein?

Answer 1

The DNA sequence of the coding region of a gene. I'll try to explain below.

Explanation:

I won't get into all the gnarly details - try to keep it simple.
A gene has a region(s) that codes for a protein - like a cookbook has a region that tells you what to add and in what sequence to add them.

So the gene has these regions called codons - simply 3 bases. IF you have the sequence:
ATGCGCAGCTCGCAG, then the ribosome sees this as:
AUGCGCAGCUCGCAG, and recognizes it as:
AUG-CGC-AGC-UCG-CAG.

The ribosome then matches the correct tRNA(which contains an amino acid) to the correct codon. AUG = Methionine, CGC=Argenine, AGC=Serine, UCG=Serine, CAG=Glutamine...and so on and so on. The gene then just defines the order of amino acids that will be present in the protein.