Once you log into your WordPress site you will land at the dashboard.
If you want to see the front of your website (what visitors see), click on the name of your website in the upper left hand corner of the dashboard. This will pull down a short menu that says “Visit Site” – click on that to get to the front of your website.
To get back to the dashboard, click the website name again and it will pull down a menu – click on “dashboard”.
I like to keep two browser windows (tabs) open at the same time – one for the front of the website and one for the dashboard while I am working on websites. It makes it easier to go between the two.