While sitting on the chair, It is important that most of the weight is on your hips and only about 10-15% is on your shins. Also, your kneecaps should not be touching the padding. This will help your back be more aligned and help you feel more balanced on the runners
Also, it is very important to ease into it rather than just fully replacing it with your chair. It is better to start with about 15 - 25 minutes per few hours for the first week and then slowly increasing the amount of time that you sit on the chair. The reason behind this is because our body is not used to a sitting position like this so we need to teach our body to get used to it.
Different people have different adapting systems and different body types so it could vary on the length of time that it can take you to get used to it. Eventually, it will be very natural to your body and your body will find the perfect position.
You can also flip the chair and sit on it however you want if you just want to relax or try different sitting positions.