I'd be surprised if there's much more to it than finding an icon that says something like "Store" and going for it.
That said, if you plan to buy apps (as opposed to just using free ones), they'll need you to use a Windows account, linked to your payment details and other personal data.
Logging into a computer with a Microsoft account has privacy implications. If this doesn't worry you, then no problem. If it does, look up something along the lines of "Use a local account on Windows 10." I assume you're running W10 on your tablet.
Have a read through these:
http://www.pcworld.com/article/3145367/windows/how-to-download-windows-store-apps-with-a-local-accou...
http://www.laptopmag.com/articles/install-apps-windows-10
for more useful advice.
The Windows store is here:
https://www.microsoft.com/en-gb/store/b/home
if you want to try via your browser.
Note the advice in the laptopmag "Enter your PC's login password and select Next to change your login account to your Microsoft account, or click "Sign in to just this app instead" to keep your PC's login as-is" if you want to keep using a local account while using the store - on occasions when it demands a log-in.
Sorry I can't be more help. W10 strikes me as a privacy nightmare and as a confirmed Wearer of Tinfoil Hats, I've never been able to bring myself to try it!
Hopefully someone with current W10 experience such as user @antipasta will be along in due course.
