I cannot tell you which is the best and easiest book, since of course I have not checked them all, but generally Anderson's books are very good, so maybe you can start with that one (Anderson J.D., "Computational fluid dynamics. The basics with applications")
In addition to use these valuable books, you can start with commercial software which has a user guide that includes both tutorial and mathematical model. I suggest Fluent which has a massive explanation for the numerical simulation tools with solved tutorials, you can use the the attached link.
If you really want to understand the finite volume method and how to implement your own code An introduction to Computational fluid dynamics, H.K. Versteeg and W. Malalasekera is your best option. However, if you only are interested in use a software and learn how to implement carefully CFD simulations Computational Fluid Dynamics: A Practical Approach by Jiyuan Tu , Guan Heng Yeoh , Chaoqun Liu is a very good option.
It seems confusing because different methods and models have been developed to solve Computational Fluid Dynamics problems with various flow physics and applications. This field is extremely experimental and theory-based! If one researches at advanced levels, it is preferred to focus on modeling his/her specific problem, and the methods which have been developing for that application. However, if he/she should start with the basics, I suggest the book of Suhas V. Patankar, “Numerical heat transfer and fluid flow,” 1980 [which is an introduction to finite volume method]
The following books are also amazing:
· H.K. Versteeg and W. Malalasekera, “An introduction to Computational Fluid Dynamics,” 2007 [finite volume method]
· Klaus A. Hoffmann and Steve T. Chiang, “Computational Fluid Dynamics Volume 1 to 3”, 2000 [finite difference method]
· John D. Anderson, Jr, “Computational Fluid Dynamics, the basics with applications,” 1995 [finite difference method]
Among many CFD books available , I recommend the Computational Fluid Dynamics for Engineers by B Anderson , and Computational Fluid Dynamics by John Anderson.
I like the book by Versteeg and Malalasekera and it is a very good choice, an other classic to add is:
Computational Methods for Fluid Dynamics 3rd Edition
by Joel H. Ferziger, Milovan Peric
and This book by Chung has more than FVM, and I used it a lot:
Computational Fluid Dynamics 2nd Edition
by T. J. Chun
Also I personally like this book a lot, it is old but a real classic By Suhas Patankar Numerical Heat Transfer and Fluid Flow (Hemisphere Series on Computational Methods in Mechanics.
It is good to know this last book is only 200 pages (very readable for a beginner) and it is among the 40 most cited books in the human history!