You arent retarded These are common issues, and I am here to help you.
Step 1- Download and Install iFunBox - http://dl.i-funbox.com/
Step 2 - Make sure you have installed afc2add tweak in Cydia
Step 3 - Connect your Device to your Computer
Step 4 - Open iFunBox and let it recognise your Device.
Step 5 - Go click the Tab "iFun Box Classic" on top.
Step 6 - From the left side panel, Click "Cydia App Install" option.
Step 7 - From your PC/Mac , drag your .deb file/s to the file explorer box on the right of the panel.
Step 8 - Restart your device for Cydia to install the .deb Application.
Step 9 - Repeat step 8 and restart your device again to make the apps usable!
After the second restart, your .deb App that you installed should be working. Congrats!
I hope this works. Let me know!