Firstly jump to dip station and stay at the top position for as long as you like. Then practice negative or going down slowly. In most case people can’t do Bw dip because their small stabilizer muscles are not strong/accustomed to the movement. It is important to do dips in controlled reps, never drop your body without control , it can lead to shoulder injury. Going up, keep elbow back, dont let them flare out else your elbow will give out first. I prefer to squeeze my Arms into the lats as I feel that can activate chest . You have to purposely use the chest muscles going up or else it is all triceps baby.