Kolasinac earned criticism from Gary Neville for his performance in Arsenal's 4-3 victory over Leicester, and concedes that it will take time to get used to English football.
Arsenal were twice behind against Leicester before eventually going on to win the game thanks to Olivier Giroud's late victor.
The Bosnia global played on the left-side of a makeshift back three that looked disorganised and nervy against the counterattacking threat of Jamie Vardy and Shinji Okazaki.
And former Manchester United defender Neville was less than impressed by the Bosnian's contribution in the build-up to Shinji Okazaki's equaliser in the first half.
Arsenal took a lead after just two minutes through Alexandre Lacazette's headed goal, but they were pegged back nearly immediately by Okazaki from a Leicester corner.
Maguire does really well to guide it across and Okazaki beats (Granit) Xhaka in the air.
On Kolasinac he added: "Sead, honestly, with his aggressiveness at the back and getting up towards the strikers, winning the ball back and breaking forward he was great for us. It's poor from him".