First of all, thank you very much for your help. Secondly, I am mining, and I've asked myself this question. I’m not sure if there is a trick to it, so I’m reaching out to see if you have any insights.
Your question is too simple, you’re just asking how to buy Bitcoin which was already answered from the post above. I don’t get why you’d ask that when setting up a mining rig is way more complicated than just buying Bitcoin from whatever platform you prefer.