France youth global Guendouzi is Emery's fifth signing and follows Switzerland full back Stephan Lichtsteiner, Greece defender Sokratis Papastathopoulos, German keeper Bernd Leno and Uruguay midfielder Lucas Torreira.
"I know him but we haven't made a move for him", the Arsenal manager said.
"To sign [a player] in the next month?"More news: Jack Wilshere signs for West Ham United
"We will only sign another player if there is an opportunity to bring in that one player, or two players".
The French teenager has been handed the number 29 shirt following his switch to Arsenal in the summer transfer window. The season begins with a game against Manchester City on August 12.
Wilshere joined West Ham this week after turning down a new-contract offer at Arsenal, the club he spent 17 years at after joining the academy as a boy.
"We've spoken about that", Emery responded when asked about who would be captaining the side when the season starts in August.More news: HBO's 'Game of Thrones' leads nominations for television's Emmy awards
"I know this player here is important for the supporters and grew up here in Arsenal but I don't give him one place in the starting 11 and it is for that (reason) he choose to leave here and I respect also this".
Emery also downplayed reports that he's interested in reuniting with midfielder Steven N'Zonzi, who played under him at Sevilla.
"I think my first idea is to have five captains in the team", Emery added. I'm very happy with him. "Now, I want to look, I want to work every day with all the goalkeepers and then I am going to decide for [who is No 1]". I explained to him my opinion and how I will want to create the team. I want to win titles, titles, titles.More news: Divers prepare to resume Thai cave rescue