Considering the amount of research I had to do to even get started in Documentum, I'm going to post a few tips to hopefully help a future beginner.
This is based on using Windows 2008 R2, SQL 2008 R2, and Apache Tomcat.
Experts...if I'm wrong on something, let me know....last thing I want to do is steer somebody wrong here.
First take a deep breath. Your installing an application, not building a nuclear sub. Yes it can be made complicated, but out of the box Documentum is pretty much a web-based folder structure with some nice bells and whistles. (not an insult to the experts here trustme...i've seen installations that make my head spin).
Always look at the release notes. If you pay attention to nothing else, check the software requirements. If it says Java JRE 1.5 then don't assume 1.6 will work. If it says 1.5 update 4 then don't assume update 15 will work just the same.
Don't forget to install the sql tools on the Content Server machine. These can be found on the SQL 2008 R2 install CD.
If you are using a 64bit Windows server, use the windows/syswow64/odbccmd panel instead of the one in control panel to configure the ODBC connection. Even after that you may still need to copy a good portion of the x86 program files/sql_stuff_folder to the program files/sql_stuff_folder to make it work.
Be prepared to image or backup your servers. You will get something wrong and wish you could step back to a previous point. I setup my servers with raid mirrors. Once I got a good stable config, I shutdown the server pulled one of the mirrors and replaced drive with a blank and let it rebuild.
Documentum is not your web server. You will need a web application server. Something like Apache Tomcat. Seems daunting at first but is actually quite easy to work with once you download and install it. As of this posting Tomcat 7 is out, but is not compatible with Documentum 6.7 (I know first hand). Download 6 and make sure you get the Windows service installer version (that is if you are running on Windows).
With Tomcat you will need to add a few Java memory settings. (-Xms1024m -Xmx1024m -XX:MaxPermSize=512m) Do this in the systray app for Tomcat (Tomcat Monitor) under the Java tab. Do not place it in the individual memory text boxes. Add the lines to the Java Options box as it has been reported to work better there.
Search for the Web.xml file in the Tomcat folder. Don't for get to insert the following code into the "JSP" section.
<init-param>
<param-name>enablePooling</param-name>
<param-value>false</param-value>
</init-param>
If it has a WAR file extension, it gets install in Tomcat. Change extension to zip and decompress. Search for the dfc.properties file and add the correct hostname, username and password (hint, you created it during the content server setup). Copy the dfc file to your desktop as you can use it for other WAR's. Copy the decompressed folder to the WebApps folder in Tomcat. Your halfway there now.
If it has a DAR file extension, it gets installed into documentum by way of the Documentum Composer (you did download it too right?).
If Composer won't start, you most likely have a JAVA problem.
If Composer Darinstaller won't install the DAR you probably forgot to run Composer with administrative rights (right click, run as admin).
LDAP authentication is easy to configure...worst thing to figure out is your distinguished name for the binding account. (Google it...easy to figure out if you are unfamiliar with Active Directory).
By now you should have Documentum up and running. At this point each of us will break off on our own path. Mine happened to be migrating from an old 4.2.6 repository on Solaris 8 with an Oracle 7 database.
