The major advantage of an E-Bike is that it gets those that are not used to be riding, on the bike. It is an easy entry. Many people just find it too hard and strenuous to jump on a normal bike and give up before they start.
The E-Bike eases you into it. In the beginning you will use much more power and as you find it easier, you will use more leg power and probably use the motor only when it is too hard to handle. Like going up a hill or when you feel tired.
If you have the intention to use the bike also for exercise and not only for fun, start slowly. Short distances and as you feel more comfortable, go further and use less power. Later on, if that is what you want, do the leg power as much as possible, well knowing that if you need assistance, it is there.
Many E-bike owners buy the bike to have fun with others. You may not have the physical condition to stay with a group or a family member and the E-Bike makes this possible. Now you can stay with them and it is up to you to decide how much leg power you want to add to the assistance offered by the motor.