Whether or not to just go for it would depend on your investment and goal. Did you spend what you consider to be a lot on your spores? If you decide not to experiment with cultivation, can you return them or resell them? Basically, are you going to be wasting your investment if you don't try, or if you try and fail? Then, what's your goal? Learning because it seems like a fun hobby, or just getting these specific mushrooms right the first time?
Personally, I'd just go ahead and try as best as you can. Use the advice you got, but don't stress about it if it's not perfect. The most likely failure is nothing will grow and you'll have wasted whatever you spent on materials and a little time. Absolutely worst case scenario is that contamination in your substrate somehow introduces a different kind of mushroom that you weren't expecting and - again worst case scenario - you don't realize it's the wrong kind of mushroom and eat it and die. That seems wildly unlikely, though.