Android

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/tablet off your shelf and boot it up after 5 years of it rotting away! then, press the Apps button, and go to Settings > 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 newer Google Play version

The latest version of Google Play supported by 4.0 is 9.4.30. You can download it here. If your device is in an older version, you can Google "latest version of google play supported by Android (Some baby-boomer Android version)".  After that's been downloaded, go to your device's file manager to open it.

Installing a new browser

Generally, this isn't always necessary, as old Android versions still have pretty decent HTML5, JS, AND CSS3 support. BUT if you still can't watch amogus memes,  Opera Mini is a pretty good option for browsing the modern web on old devices. You can download it on Google Play. (NOT SPONSORED)

Wrapping up