There are as many different reasons for reloading as there are recipes for BBQ sauce! While most would like to think they can save a lot of money by reloading, it's not always true. Unless you shoot a specific caliber a lot (like competition) then you won't be buying large bulk quantities of components. Add in the cost of the press, dies, measures, scales, case trimmer, micrometer, guages, loading blocks, storage boxes, primer tool, and on and on and you will begin to realize that unless you're having a lot of fun then it might not be worth it. Personally, I load alot because I like it, but I still buy factory ammo too.
Sometimes when starting a new load I will have 3 or 4 manuals open at the same time for comparison. You need manuals. However, you can also find many good loads on-line. I would search for the caliber first, then some of the powder/bullet manufacturers also have data available on-line.
You should always start with minimum pressure loads and work your way up. There are many things that can affect pressures other than the powder charge, like bullet diameter, barrel diameter, seating depth, burn rate, primer selection, even temperature. Be Safe.