Symbian^3

Preparing your device

First of all, make sure your device is connected to the internet in some way, if it's not, get the gotdamn dusty phone off your shelf and boot it up after 8 years of it rotting away! then, press the Apps button, and go to Settings > Connections > Wi-Fi, and I'm not gonna explain this one because I'm assuming you know how to connect to a Wi-Fi network.

Installing a new App store

Now, go to the official SIStore website by clicking here. (not in your device, in your PC's browser.) Go ahead and download the .sis file for your device's Symbian version and plug your device into your computer using a Micro USB data cable.

 Select Mass storage as your device's default USB mode from Settings. If your device says Charging... when you plug it into your computer and it won't appear as a storage drive, try a different cable. If you don't have another cable, STOP using your broke ass cable and make some money and go buy a high-quality cable.  Anyways, Move the .sis file you downloaded to your device's download folder. 

Then, disconnect the cable from the device and open File Manager. Once opened, go to the download folder and tap on the .sis file. If a Certificate Expired error appears, Go to settings and set the year to 2012 (no it won't take you back to 2012) And try installing the .sis file again. Side note: You'll most likely have to do this every time you want to install an app to make sure no errors appear, but you can set the year back to *current year* if you want to, or even try to install an app with the year set to *current year*.

What you just installed is called SIStore. SIStore is an archive of Symbian apps from the Ovi Store and new apps made by enthusiasts. You can also download themes and Custom Firmwares, but SPOILER ALERT: Custom Firmwares are NOT NECESSARY at all for resurrecting Symbian devices. If you install a custom firmware thinking it's necessary and then you turn your device into a brick, I will laugh at you. Feel free to browse around and install your needs (NOT a cfw).

Installing a new browser

Open the SIStore and select the Apps icon in the top. Then, Scroll down until you find the internet category. Press it.

Now, install the Opera Mini app. If nothing happens, close your useless stock browser and try again. When a popup shows up with the title of Opera Mini's .sis file, press it to start installing it. 

Choose "Mass storage" as the install location. After that, you can start browsing modern websites.

Wrapping up