I've just got out of a recovery period (8 months) after an operation to get red of gynecomastia , 2 years before that I used to weigh 100 kg and I dropped it to 67.5 kg by basically not eating anything and doing cardio for an hour everyday , it had a bad effect on me ( no shit ) but it did the job. now I weigh about 81 kg and I've been cleared to get back to work out but now I want to do it right from the get go but there's so much advice online I don't know where to start , the coaches in my GYM want me to do cardio for 1 and a half - two months before lifting anything! where to start ?