My recommendation. Jean Meeus, Astronomical Algorithms book. My copy is dated 1991. There is also Stellarium software, Starry Night, and SkySafari software used by many working with backyard telescopes (me for example). The grids and conversions are done automatically by the software like projecting a view of the sky for your location and the azimuthal grid. This shows altitude and azimuth to point your telescope for a specific target or just go outside and enjoy a view using binoculars or just unaided eyes.