I worked in the USA for 2 years and returned and worked in Canada for 3 months of 2014. I have a W-2 and 1042-S where do I enter each of these amounts.

These sound like US documents. You must file a US tax return.

Yes they are US forms, but I must enter on Canadian forms I believe, but where ?

If you are required to complete a Canadian tax return and you are required to include these as income then you will enter the amounts on the Foreign Income slip.

You may need to contact the CRA if you are not sure if you need to include this income or not.