I think it would be a really good idea for you to watch a video about reloading. Resizing brass, any brass is an absolute and necessary step. Be it neck sizing for bottle neck cases (rifle brass that has shoulders), or straight walled cases such as handgun cartridges, auto loading (45 ACP type) or revolver brass (38 spcl. type), all have to be resized. And all die sets come with a resizing die.
As for crimping, you don't need to crimp most bottle neck cases. After resizing the brass will have all the neck tension necessary to hold the bullet firmly. There are a couple of exceptions though, tublular magazines and some auto loading rifles may need a crimp to prevent bullet set back.
Auto loading brass, such as 45 ACP, utilizes a taper crimp which is an integral part of the setaing die, and should only be crimped to the point any belling of the case mouth is removed. These type cases don't use a crimp for neck tension, and over crimping will cause reduced neck tension, deformed bullets, buckled cases, and excessive head space.
Revolver type brass, such as 38 spcl. utilizes a roll crimp which is also an integral part of the seating die. These cases need to have a firm roll crimp into the canelure of the bullet. Although it important to use a good firm crimp on these cases, over crimping will buckle cases. It is also necessary, in my opinion and especially for someone new to reloading, to keep these type case trimmed to equal lenghtes within SAAMI spec. so your cirmps will be consistent.
GS