its very confisive in english to use the could and would....anyone can clarify it?

Both words have a number of uses and it is impractical to present all of them here. Start by reading about the words and [url=http://grammar.ccc.commnet.edu/grammar/auxiliary.htm ]HERE [/url].

If you have more specific questions after reading those, please ask us.

Here are a few more links that might interest you.

Should- could- would
Could and would

And you can always use the search box above as well.