I would recommend picking up at least 2 and even better 3-4 reloading manuals, do a little research into the calibers you are reloading for and take a best guess starting load or two for each. test the loads at the range and evaluate the resulting accuracy, velocity and/or recovered bullet data. what works for one individual and their firearm my not be the best overall round for you and your firearm. barrel twist, length, action, wear and even climate can play a big role in ballistics in general.
all said, that doesn't mean you cant get a few of the forums members pet loads and start from there, I am just recommending not skipping too many steps in your new adventure.