I’m new to DevonThink also. I found it helpful at first to just import some of my files into DT3 as a sample to experiment with and test program functions.
I also found it extremely helpful to download the “Take Control of DevonThink 3” book to my iPad, and then go through it section by section. As I did so on my iPad, I identified and tried out the features in my DT3 program. I didn’t try to do the whole book in a day, but rather went through it an hour or two at a time. This way I got familiar with some of the features of the program I may not have discovered on my own, or wouldn’t have known what to do with if I found. This process was most helpful.
After going through the book and playing with DT3 for a couple of weeks, I then transferred all of the files I intended to keep in my main DT database, and then added one very large folder of indexed files and archived my email to a separate database. Then I started figuring out my workflows for sending web clips to DT, transferring new pdfs into DT, using the OCR functions, and playing around with the AI suggested filing system vs. building some new hierarchal folders (“groups” in DT talk). Next I progressed to using DTTG by reading articles, forum posts, the manual, etc. and trying to work out any issues I encountered.
So over the first few weeks I learned the basics of the program, and then more features, and then started really working with the program in conjunction with DTTG. By approaching it this way, it significantly reduced for me the “overwhelming” and “steep learning curve” some experience. Your milage may be different.
One other comment. You expressed some concern about programs that you put important data in, and then can’t get out or it destroys your data. Remember that when you import data into DT it only makes copies. You still have the original files unless you choose to delete them. And taking files out is just as easy as putting them in; drag and drop easy. My understanding is that unlike some programs, DT does not convert your files into some proprietary format, but rather they stay the same. So no worries about covering them back to something you can use if the program becomes unsupported or you choose to move to something new. These features of DT made it particularly attractive to me, and one of the main reasons I decided to purchase and use the program.
I hope this has been helpful.