Similar to the London system, the Queens Gambit opens with d4, but the similarity stops there as White strives to control the centre quickly with c4 played on move 2 – if Black allows. It’s important to develop and castle before attacking.
These short examples are the declined version, Black can of course take c4 on move 2, which is known as the accepted gambit, in which case play e3 or e4 and win back the c4 pawn.
This is a similar set up to the London opening with some subtle differences:-