What do I need for my MP3 player to work? (enV)

I already have the little card.. it has music on it (I've used it in blackberry and sidekick lx)
The retailer told me I need to buy an entertainment package with the hookups for the phone.. I'm so confused. When I put the chip in my phone now, nothing is different and there's no music in the folders.

First you need to format the mem card from WITHIN your phone. <menu, settings & tools, memory, card memory, options, format>. Formatting will ERASE your card so you may want to transfer you songs somewhere else temporarilly. Once formatted in your phone, the phone creates folders on the card - my pics, my vids, my music, etc. Remove card from phone & hook card to your computer. Open the "my music" folder (that the phone created) on the card with your computer, then drag & drop your mp3's in. Once the card is loaded with mp3's & back in you phone, arrow up on the front keypad & the player will start, add songs to library & start playing mp3's. You do not need the entertainment pack...