The hard one for understanding. If you read the English message, it is all clear. The point is that you have some contacts saved to this device and when you install Telegram these contacts won’t be added to the Telegram account. The Russian variant says “Контакты с этого устройства не будут импортироваться для этого аккаунта.” I understood it like there are some problems with my account and because of that, my device’s contacts won’t be added to Telegram account. I suggested light version of the translation trying to keep the idea.