How to be registered as entrepreneur in Luxembourg

Dear all, does anyone of you from non-EU country had an experience of registering him/herself as a (solo) entrepreneur in Luxembourg?

I do want to proceed , but am not aware of : 1. what should I start from , 2. does this registration gives a non-EU person the right to stay full time in Luxembourg or I will be limited with the number of days per year?

Would appreciate any advice or reference to your contacts who might be aware of the procedure.

What I have found so far:
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