W231/HP38 and Unique are two good powders for a newbie to start reloading .45ACP. Both work very well in the caliber for multiple bullet weights and both are bulky enough that they fill the case enough for a newbie to see they are charged and charged the same. Primers in .45ACP will matter little. Make sure tho, because some .45ACP cases are SP and some are LP, that you use the correct size.
Powder choice is 2nd to what you want your ammo to do. Many times bullet weight and the velocity you want to push that bullet dictates the powder. Many times your manuals will tell you what powder performed the best for them with specific bullet weights. I've found for new folks, the powder that fills the case the most, while giving the performance they want works best. As one's experience expands, so will their demands of powder. For some, that are cautious and experienced, powders that use the smallest powder charge, and/or cost the least per powder charge are what they use. For others, powders that can be used for other calibers or other bullet weights takes preference. Read your manuals, glean all the info you can from this and other firearm forums, and load safe, reliable ammo, and soon you will be telling others the answers to this same question.