If you run TYPO3 4.1 or more, just download the extension from the TER, install it and get rolling.
If you run TYPO3 4.0 or less, you will need to place the Prototype library yourself somewhere on the server and configure the path to it in the extension's configuration. You have to give the full path starting from your site root. Note that this is necessary only if you want to use the feature for viewing the extra data (see User Manual below), but it's a useful one...
Read the paragraph below if you are already using cc_devlog.
If you are already using cc_devlog and want to switch to devlog without losing your existing logs, you can simply go to your favorite database administration tool and manually rename table tx_ccdevlog to tx_devlog BEFORE installing devlog. Obviously you should then remove cc_devlog.
