Tips on how to do exercises in the gym

Hi gymbros,

I just joined the gym and I'm looking for a third source to learn how to do exercises well. The trainers are not always in the room... and when they are there they are often more busy talking to the girls than following those who are new...

I wanted to ask you: are there really clear apps or sites that visually explain how to use machinery and tools correctly? Such as chest press, pulley, leg curl, dumbbell exercises etc.

I need well-made videos or animations, perhaps with an explanation of correct execution and common mistakes to avoid. Something I can look up on the fly while I'm at it in the room without having to disturb anyone. All this to prevent it from destroying my back or shoulders

What do you use or recommend?

Thanks in advance!