Start with a manual that has a good, comprehensive "how to" section. Lyman, Sierra, Speer and Vhit all fit that bill, but the Vhit manual only has data for their powders.
Just about everything you will read in "how to" books like "ABC of Reloading" and the Lee "Modern Reloading" will be covered in these manuals, with the added advantage that you dont then "have to" buy an additional book if you start of with a manual as opposed to a how to book.
Manuals by bullet manufacturers are more flexible because they cover a range of powders by different manufacturers, and you'll find that starting loads for one 150grn bullet are interchangeable to another 150grn bullet. However, loads are not interchangeable between cup and core type bullets and the lead free, all copper types.
I'm glad to see at least one potential reloader asking about getting a manual, rather than jumping straight in and asking "who has a load for.....?"
Manuals are published sources and are 99.99999% guaranteed to be correct and safe. Some bloke on the interweb who calls bullets "heads" or refers to primers as "caps" wouldn't fill me with confidence.