Beginner needs help using Organizer

So, now to answer question 4.  I know of no good books devoted solely to the Organizer but you may want to browse through the online user guide.  Here are some general thoughts in no particular order:

• To make sure all of your photos and videos are in your catalog, I suggest using the Import in Bulk dialog.  You can add all of the drives or main folder paths where your files are located and the program will search for all of them to place in the catalog.

• How many catalogs?  I can think of no reason to have more than one catalog.  There is no known limit to how many photo or video files can be listed in a single catalog.  My current catalog has about 220k media files.  Any potential reason for having more than one catalog can probably be addressed by the tools available in a single catalog.
• Location of files?  Depending on the size of your SSD hard drive and the number of photo and video files you have, you are probably better off just storing them all on one drive.  If you are unable to add an internal drive to your computer, then there is no reason why you can't simply store all of the files on an external drive.  (But it is also wise to backup all of your media files on a second and/or third external drive.)  I can find no evidence that an SSD has any benefit for storing the media files that are being organized by Elements.  But there is a benefit to have the actual catalog database files stored on the SSD, particularly if you are backing up the catalog frequently, using the new tools available for that purpose in the Organizer.  If you are going to be performing face recognition on your catalog, each file creates a small text file in the catalog.  These small text files take an incrementally longer time to copy than large media files.  The read/write speed of an SSD makes this process a lot faster.
• Tips for creating tags and albums?  The use of these tools depends on your needs.  The whole purpose of tagging photos and videos is to be able to easily find them on command. Frankly, the Artificial Intelligence used by Elements is so good in identifying the contents of photos and tagging them with Smart Tags that there is no longer a need to manually create keyword tags.  Of course, you may have some special needs that require you to tag the photos with your own unique tags.  Or you may be as obsessive/compulsive as I am to make sure that every photo is tagged with terms that are familiar to you.  But I would say that if I were to search for bird in my catalog, Elements would present me with 90% of the photos that I wanted to find.  And if I search for peacock, I will get the bird itself as well as close-ups of peacock feathers.  There may be some, or even many, false positives.  But you should try it out before embarking on a plan to manually tag all of your photos.
• Face recognition gets better each year.  So if you are the family historian, it is worth spending time to go through the process of naming the people in your photos.   There are several shortcuts to make the process faster.  But that is a whole separate subject.  I suggest you start the process and then ask any questions you may have on the forum.
• There are some differences between keyword tags and the People, Places, Events system tags that can be generated in the Organizer.  I am a heavy user of face recognition to create the sytem People tags.  But I don't use Places or Events tags.  The naming of places is a matter for personal identification.  So I use keyword tags to name my places.  If I go to Disneyland with my grandkids, I would rather just tag the photos with a keyword tag of Disneyland rather than use the map services designation of the area:  United States> California> Anaheim> Anaheim Resort etc.

• Adobe has to use a third party map service for this tagging and the service has changed over the past few years which has resulted in a huge mess for those who have relied upon it.  I am therefore glad that I stuck with keyword tags for my geo-tagging.  However, if you use geo-tagging of files from your camera or smart phone, the program can automate the process somewhat.
• I also use keyword tagging for my Event tagging rather than the system Event tags.  This is simply a personal preference and I don't have anything negative or positive to say about it.

If you tell us a little more about your specific needs, we can perhaps offer some additional advice.