"My Sites" does not appear but network is detected

I am trying to set up a network for testing on my localhost on a Mac but the My Sites button is not showing anywhere on the toolbar. I read the codex and followed all the steps. The setup was successful (the network shows as “detected” under the tools menu) but I don’t have the “My Sites” button anywhere on the toolbar. I emptied the cache just in case and logged in again but still nothing. I have only one site at present and that is working but I want to work on several others which will be entirely separate from each other–hence the network.

FYI, the only glitch in the setup was that there was no .htaccess in the WordPress folder. I found one located outside WordPress: MAMP>bin>PHPMyAdmin>contrib>htaccess. I created a new .htaccess file and placed it in the WordPress folder and also changed the contents of the original one (made a BU first). I don’t know if I did that right or if I’ve created a conflict.

Ultimately I’d like to switch to a sub-domain system but I’d be happy to just get my local network to function for now. I am a designer who is inexperienced as a developer and I’m not sure what to do under the hood with the code. Please be detailed with any instructions you can give me.

My setup: Mac, MAMP Pro, WP 3.3.1, localhost

Thanks for any help you can offer.