This, it's an offshoot of chemistry. While there is some room for error, it is not great depending on the ingredients used and which recipe you're following for what ammunition. There are many different kinds of powders and not understanding their intended use can be catastrophic. Adjusting your loads should be done very, very gradually and slowly, as large adjustments can cause a spike or drop in pressure. Poor quality primers can also fuck you, so make sure you read reviews and reviews that don't out themselves as user-error.
To begin I would recommend a Lee Loader kit that's fairly inexpensive and forces you to pay attention. Purchase an up-to-date manual, do not look up handloading recipes from 20 year old forum posts.
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Understand the concept of what you're doing before you move on to proper equipment that costs hundreds of dollars.