TikTok is a social media platform built for smartphones. You can use it on a computer, but this guide will give instructions for using the app version.
One decision you'll need to make is whether you want to set yourself as a "Business Account." You can set this up under "Manage account" in your Settings. However, there is a huge con to being a business account and that is you will not be able to use any copyrighted music, which means most popular sounds and clips will be inaccessible to you. One nice thing is that you can switch between the two types of accounts so you can always experiment and see which will work best for you.