The exact steps on how you go about retrieving your bank account statement online will vary depending on which bank you're using - each one will have a slightly different set-up.
With most modern banks though, the first step is to sign-up for online banking.
It won't always be activated without you first requesting that service, so get in touch with your bank.
Secondly, my online banking system allows me to access my accounts from any device through the bank's own website, however my bank also has an app that I have downloaded to my phone.
This is a much quicker way of finding out what's left in my account during the month, so I'd recommend finding out if your bank has an app too.
Finally, security is a pretty big deal when it comes to online banking - so it's vital that you get up to speed with the details your bank will request before you can access your account via the web.
Many banks these days give their customers a hand-held device that uses the card's chip & pin to add extra security.
More details should be available from your bank - so maybe it's time to take a trip there in person!