There are many different types of period products, and it is really up to each individual to find the type they are most comfortable using. It may be useful to talk about options with a trusted adult or older sibling who can offer some thoughts and advice.
It is important to change pad and tampons regularly throughout the day. Menstrual fluid has no odour until it meets the air, however a pad or tampon left in place for too long can begin to smell and it can lead to infection.
Tampon packets contain instructions (and pictures) for use. There is a large range of different types to choose from, including 'slim’ versions and some with applicators which may be helpful for someone starting to use them for the first time. When a tampon is properly inserted it can't be felt at all.