My first load manual was Speer #11. At the top of the page was a list of the components and the rifle that was used for testing. Who pays attention to that stuff? First time I Lake City once fired 308 the start load from the manual brought the powder to just below the neck/shoulder junction. 2/10's of a grain was part way up the neck. YIKES!
I started buying manuals and picking up load pamphlets when I was at the gun shows or gun shop that sold reloading supplies. Eventually you'll get enough info to reload what you have at hand.