t+3 settlement

Hi guys, cant do a search for T+3 so no idea if this has been covered, but i was wondering when contracts through Brokers are settled T+3 if i do an intraday trade how does it work? Example: I have $1000 in my account, i buy $2000 of shares at 10:00am, sell them at 2pm for $3000, in 3 days...