Sandler joined City last summer carrying an injury.
"I've been back in training for about six weeks after tearing my meniscus and I had my first full game against Barnsley in the Checkatrade Trophy," Sandler told City's website.
“It's a lot different here in England. Physically, it's much more demanding and Pep wants us to play a certain way and one that I am, of course, learning."
Sandler also discussed what it's been like learning to play 'the Guardiola way'.
“You have to be confident on the ball, able to receive passes under pressure and be able to start playing out from deep positions – that's how I played in Holland and that is why I was brought to City.
“I think my playing style is the reason I'm here now because I play in a way the manager wants.
“All the central defenders we have at City are top-line players and it's a privilege to be able to train with them and learn from them every day.
“I watch every game closely and during every training session watch what they do, how they cope with the pressure in certain situations and suchlike.
“It's really good here – the players and the staff have been great with me and the I really like Manchester as a city and the people are really nice, too. I'm really happy.
“The main thing for me was to get fit and I'm getting there – not quite at the same match fitness level as I need to be yet, but obviously I'm working hard to be 100% fit and ready to play if needed.
“If I can get an opportunity to be involved in any of the squads in the New Year it would be fantastic, but I just have to work hard and see what happens."