To understand Conditional sentences, watch this video
You can also have a look at this slideshow
Conditional sentences from Carmenramirezgonzalez
Finally, go to the section Practice Bach and try to complete the exercises on conditionals you can find there.
Now, you're ready to use conditional sentences and do the exercises in the book.
For extra information, download this theory about conditionals and wish sentences.
Now enjoy this song by Bruno Mars.