That really all depends on the sorcerer, some prefer to keep to themselves, others see no reason why they shouldn't be blatant about things-especially so if they've no reason to fear otherwise.
Sorcery..it's hard to explain. It has it's own rules, which usually include bending the rules of physics, and allowing your mind to accept what couldn't happen.
As from one who's learning herself, unless you've some skill already, I wouldn't suggest trying to make a portkey just now. The more focus and complex a spell is, the higher the energy drain will be, especially for someone who isn't used to the strain and new to practicing it in general.