How to download 4shared.com app files to my iPhone 3G?

How do I download 4shared.com app files to my iPhone 3G? I have a iPhone 3G running on 4.2.1 and it is jailbroken. I have iFile downloaded and I can't download the Facebook app or instagram app because I need iOS 4.3 so I have to download them from 4shared.com because you can't get installous or anything like that off of cydia because they shut down.

You have to jailbreak it and install ifile. To jailbreak go to www.jailbreakme.com.

Go to pandaapp.com, download facebook and import it in itunes… Then sync your iphone. Thats it.
p.s.instagram no longer supports ios 4.2. You can download it, but it won't work (i tried).