Yeah, that link [MENTION=60100]Rabbitbait[/MENTION] is a very good resource. I am a very experienced DM and still found it useful. Partly because I read up on the bits my PCs are NOT doing. That way if they go off the rails and end up in another area, I at least have an idea of how the adventure could flow and the basic encounters to expect.
As a new DM, I think one of the best things you can do is to just be confident. If you worry about "ruining" the adventure I suspect you are more likely to do so. If in doubt, make something up, you can always rearrange things later. The more confident you seem while doing that, the more engaging the adventure will be. The more times you make something up on the fly in an "uh oh, what do I do now" moment, the more confident you will get with it.
As a new DM, I think one of the best things you can do is to just be confident. If you worry about "ruining" the adventure I suspect you are more likely to do so. If in doubt, make something up, you can always rearrange things later. The more confident you seem while doing that, the more engaging the adventure will be. The more times you make something up on the fly in an "uh oh, what do I do now" moment, the more confident you will get with it.