If you possess a Blue Unlock icon, you gain 5 gold in the income phase for each draft marker you have in the 5-gold drafting row. I.e. Two draft markers would earn you 10 gold.

You do not need a Blue Unlock icon just to place your draft marker to draft cards from the 5-gold row. You would not gain income from them, however.

All Building card effects may be used only once per round since you have to exhaust the card when you use its ability once — this applies whether you want to use the card for its special effect or its tech icon. The only exception are buildings with the "do not exhaust" icon (see page 8 and page 20 rules).

Research Point (RP) cards are simply a way to track how many RP you gain during the current age. When you gain RP, you can either just remember how much you gained in total and then spend them in a research action, OR you can take research point cards. Either way, you discard RP/cards when you do a research action. Superfluous RP are forfeited.