The best way to start training is to contact a competent trainer. Starting to practice on your own, you risk doing something wrong and harming yourself. Also, you may lose motivation for homework, and the coach will be the reason to continue to visit the gym. If you are too lazy to come to the gym to run on a treadmill, then buy it and run at home. You should have some variety in your exercises - if this is not the case, then training will quickly bore you. You can go to the pool, ride a bike, and even play ping pong with friends with
this right equipment - you have to have some other activity that you like.
Also, do not forget about proper nutrition. It doesn't have to be a diet - remember that a diet is always limited in time, and you need to eat right at all times. This does not mean that you should once and for all give up sweets, starchy foods, fried foods - you must learn to eat so that these foods do not bring you extra pounds. Your trainer should help you adjust your diet.
In any case, I wish you good luck!