Gargling the mouth and cleaning the nose

When you do ghusl, do you need to make sure you make the gargling noise when rinsing your mouth to make sure you rinsed your mouth correctly and properly? Because it feels embarrassing when you make the noise because other people can hear you outside the bathroom and they would know that I'm doing ghusl and I'm impure? Also, do you have to sniff water up your nose and touch/reach the beginning of the hard bone/part of the nose or is just putting water without sniffing ok because I find it hard and impossible to actually sniff the water into my nose? Also for ghusl, are you allowed to first take shower and rinse your mouth and nose while you're taking a shower? Does this count as ghusl and is it valid?