Need lamen explanation of ionic vs. covalent bonds

[julia*]

Hi I am new on here and also new to science. I am in College getting my Biology 12 and Chemistry 11. I am having a really hard time understanding the difference between the ionic and the covalent bond. I am having trouble understanding:
a) the net charge that creates an ion
b)the ionic bond in general
c) the sharing of atoms in a covalent bond. what determines when two atoms will share electrons!

Thanks to all you lovely smart science people out their one day I hope I will be too! If you could do your best to answer this as simply as possible I would be so grateful!
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution

[Borek]

Try to read about bonds in some other book than the one you already know, check wikipedia, check http://antoine.frostburg.edu/chem/senese/101/index.shtml. The more sources you will try, the higher the chance one will click with you. These are very basic concepts, it is hard to help you not knowing what the real problem is.