As with many ratios that pertain to the fundamental aspect of a company, the lower the ratio is could be there is value to be had. However, you need to be aware because a lower price to book ratio could also be an indication there is a fundamental issue at hand that needs to be addressed.
The first part of the equation is market price and this can be looked at in just about any manner. Market price could just be simply left at that while you figure this equation, but if you know the market price is down you can figure out why and that can help you in understand this ratio better. The second value of the equation is book value and that is straight forward. It is important to know how an equation works because if something seems off, you need to be able to pick it apart and find out why.
With that, be sure to begin implementing this new study into your current setup slowly and see if it brings you value. Search the Internet and see how other people are using this and find ways to have it bring more value. Also, join an investing or trading community, as this is one of the best ways to get real time feedback and converse with people who are actively participating in the market. Lastly, if you have hired an investing professional, consult with them and they would be more than happy to walk with you through an explanation and example. Price to book is a wonderful data point to help guide you in the right direction and it should certainly be added the toolbox of your investing knowledge.