What file did you download and where specifically did you place it on your hard drive? You have a some options when it comes to using the hatch patterns you downloaded. You can take the pattern definitions themselves and append them to the end of your acad.pat file, you can load them individually or you can group them in a custom PAT file that can be loaded separately. Whatever method you use AutoCAD needs to know the 'path' to the file so it can find them when called upon. Which method do you want to use? This site offers free wood grain hatch patterns too. Epson stylus photo r2400 manual.
For more general knowledge: there are many woodgrain patterns, and a myriad of hatches, on the internet. Some are free, some come in packages with fairly.