There are ways to emulate the look and actions of a mobile device using a desktop or laptop computer.
Chrome
When viewing the public side Welcome page in Chrome, you can select F12 on your keyboard. It will display tools on the right. Select the wheel/gear in the top right then Devices on the left. A list of devices will be display that you can choose to 'emulate' how the page will look on that mobile device.
Alternately, you can make sure the icon shown below is selected then use the drop-down in the top right labeled Responsive to select the desired one. If the desired device is not listed, select Edit at the bottom of that same list of devices and put a check next to the desired device name. Select Responsive again to view it in the drop-down and select the one you need. Once you set the dimensions, you may have to select the browser's refresh icon to display the mobile image in the correct size.
Firefox
In Firefox, use Crtl + Shift + M and the screen will be displayed in a smaller size. At the top it will show the display below (Responsive). You can adjust the pixel size to match device screen sizes.
For any browser, you can also drag the sides of the display to adjust the size manually.