The basic mechanics of the carry trade is that you are looking to buy a high interest currency compared to another currency that has a low interest.
The difference in this interest will be paid to you from your broker. Normally the interest payments will be made once each weekday with a triple payment on Wednesday to cover for the weekend period.
An example of a carry trade could be as follows; if the EURO has a 3% interest rate and the USD has a 1% interest rate you could look to buy the EURUSD. The difference in interest rates which is 2% would then be paid to you by your broker.