"My first piece of advice is to work hard on your research before you go if you want to make your trip enjoyable and rewarding. I plan my trips very carefully for at least three months before I leave, reading about the places I am going to visit on the Internet and in books."
Source: Cambridge grammar for IELTS.
Could anyone please help me what kind of clause if the bold part? Is it a reduced adjective clause that modify the whole sentence?