What is the idea behind the keto diet? It is to reach ketosis which means that you are burning fat instead of carbohydrates. In order to do so, you need to eat a diet with very few carbohydrates, but with a lot of fat.
Essentially if you are afraid of fat, a keto diet is not for you. Otherwise read ahead. Things you need to stay a way from are: sugar, pasta, rice and starch.
First thing to do is probably to cut out candy and sweets, but that might be a tall order for a lot of people. One point to start might be to substitute all your candy with dark chocolate. It is a bit less sweet, and it also has the benefit, that you will eat less of it. For me personally I will eat a 100 gram bar of milk chocolate in one go, but I only need 50 gram of dark chocolate.
Soft drinks are also a big no, no here. The easiest way to get rid of them is to start drinking sparkling water, add a slice of lemon, lime or orange to improve the taste.
When it comes to cooking, start to experiment with eating meet and vegetables only, without any potatoes, pasta and rice. Use a lot of olive oil or other cooking oils that are healthy.
If you start with these steps you have started your keto journey and might well be on the way to reaching your weight goals even without ever going into a full ketogenic state.