iTunes gives you two ways to transfer songs to your iPhone, iPad or iPod touch.
Before transfer songs to iPod touch
You should download and install iTunes on your laptop firstly. Take it easy, this app is free. After installing, run it and drag songs from computer to this app, all songs will be auto added to iTunes library.
Way 1. Sync all songs to iPod touch from iTunes library
You can follow Clyde’s steps to do that to sync all music to your iPod touch. But notice that this way requires you to erase all media files on your iPod before sync.
Way 2. Add several songs to iPod touch from iTunes library
iTunes offers another way to, which I think is better than sync.