Arsenal signed Declan Rice from West Ham United for £105 million on Saturday. The England midfielder was their third signing of the window after Kai Havertz and Jurrien Timber.
"Every signing that we have made brings special things to the team," Arteta told reporters ahead of Arsenal's pre-season friendly against a Major League Soccer (MLS) All-Stars side on Wednesday in Washington.
"We are very pleased as you can imagine that we signed the players that we wanted. We've signed them early and they've started to adapt to the team really fast.
"We have some time now to prepare and for them to get the best chance to express themselves in the right way."
Asked if there could be more signings before the transfer window closes on September 1st, Arteta said: "Let's see, there is a lot of time still in the market and a lot of expectation in some of our players.
"We will be alert, there is still time to do things, there is still time for exits as well obviously. I'm sure things will move."
Arsenal begin the new season at home to Nottingham Forest on August 12th.
