If you are reloading your first buy should have been a good reloading manual even before you b ought your press. You should have gotten a chart with your dies that gives you the powders and charge weights you need. Go to lee precision and you can get the info.
If you are using (or have bought) any of Hodgdon, Winchester, or IMR gunpowders, they have a partial list on their website (you must click the "I Agree" button on it): http://data.hodgdon.com/main_menu.asp
Look up the bullets you have purchased (or will be purchasing) by caliber, bullet weight, bullet brand and type.
It is ALWAYS best to get at least one reloading guidebook. I use the Speer book, the Lee Modern Reloading Guide, and the Barnes Reloading manual. I have found the Lee book has the largest range of bullet and powder recipes for any given caliber.
It is very dangerous to simply go on what someone else tells you to load, for instance, if I were to tell you to buy so-and-so bullets and such-and-such powder and load them so-many-grains-of-powder-per-charge, you would really have no way of knowing if this was a safe load to use. A reloading guide will have minimum charges and maximum (SAAMI-max spec) charges listed, with corresponding muzzle velocities. This will be your safest and most reliable course of action.
An underpowered charge can lead to a squib load and possibly an obstructed barrel, and the next shot thru the gun can potentially explode the chamber.
An overpowered charge can out-and-out blow up your gun, possibly with you hand along with it.
An incorrectly loaded round (loaded too short) can lead to serious overpressure, with same results as an overpowered charge.
An incorrectly loaded round (loaded too long) can lead to a slam-fire (sometimes), which is dangerous!
Don't get me wrong, reloading is lotsa fun, and saves money, you just gotta be careful about what you load. A manual is a must.