hello

hello im new here and i wanted to ask if there are some risks doing excersises
especially if someone doesnt know how to strecht properly and what are the signs
he must stop.

Hi bud, well stretching isn't that hard, you just have to be careful and listen to your body. If you push too hard you can probably feel pain and do some damage but you don't have to be scary, i recommend you always do the warm up for better results and preserve you from harm.
Try different intensity and exercise, if you look around here you can find out plenty of it, but i suggest you to start from DLD newbie routine if simple and can grant you some good gains, and stretching is well explained.
Another suggestion is to use some baby powder so you won't loose your ok grip under the gland.

Hope i was helpful

Take you time, be gentle with yourself as you learn. As you become more comfortable add intensity. You will become accustomed to the training very quickly!