Not a silly question at all.  This topic is probably one that is most people struggle with.

Two videos to watch that address just this subject:
Normalizing Data
Too Many Tables

Theory and reality often don't make sense and don't work well together.  An example would be storing a shipping address in an order.  Theory would tell you that you would not store it in the order.  Reality has shown a good reason that you might want to store that address for historical purposes.  If a customer were to move, you wouldn't want that address to change.  You would want to know for historical purposes where that order was originally shipped.

For question 2 Helper Data

Another thing to consider is accuracy and consistency in how data is entered into your database.  When I want to control how users input the data and reduce errors, I will put common data into a separate table.

Using your ranks as an example - you could have all the ranks in a list strictly as a lookup and the value could be stored as a link to reduce redundancy.  You could also use that same table in a different manner to actually insert it into the records to reduce typing errors and promote consistency.  
Example:  Capt., Catain (misspelled), CPTN, Captain.  It's more efficient to store that as ID 1 - Captain in the lookup table or as I like to call them support or helper tables.
Richard put out another good video how to consolidate multiple small look up tables - check out the Helper Data.

^^Dan you beat me to it!  I couldn't remember the title of the video.

🤪

Oh, thank you guys for this fast response :)
Yes the accuracy an consistency are arguments not to neglect and a good reason to create a separate table. Is what you call a lookup table? (so you use the lookup wizard to link the field with the lookup table?).
Thanks also for the recommendation of the Helper Data vid. I didn't know about that one.
Many thanks an kind regards,

Actually the Lookup Wizard in tables is one of those things listed on the Evil Access Stuff list.  That wizard causes to many issues and is not recommended.
If you want to use a look up table refer to the Relational Combo video instead.

thx Scott, I've already watched the suggested the helper data video and it nailed it. I will also have a look to the relational combo vid. have a nice weekend

You bet. Glad you found those helpful.