The simple answer to your question is: Whenever you feel you are ready to start building your own Team of Downline Members.
In other words, Biljana, do you believe you've gained enough "BASIC" knowledge and understanding of how this program works, to begin building a workable Team for yourself? If you do, then I suggest you start, as you say "buying PSAs" right now!
After all, this, along with promoting your SFI business & selling TripleClicks products, are how you will be able to build a lasting monthly income for yourself. And what better way to do it than to have a Team of your own to share in the making, and profits, of your business?
The simple answer to your question is: Whenever you feel you are ready to start building your own Team of Downline Members.
In other words, Biljana, do you believe you've gained enough "BASIC" knowledge and understanding of how this program works, to begin building a workable Team for yourself? If you do, then I suggest you start, as you say "buying PSAs" right now!