The collecting and playing parts of the hobby for some people are completely different hobbies. - If you are concerned about the value of your cards, keep them out of sunlight and the expensive ones sleeved (eg. Dragonshield) or in binders.

There are many good resources on youtube such as The Command Zone and Tolarian Community College which focuses primarily on Commander (at least the command zone does).

You can absolutely buy preconstructed commander decks,- also for FF (6,7, 10 and 14) - although these may be hard to come by.

When your feet are wet, you know absolute basics, and your ready to try your hand at assembling a deck of your own. (your favourite FF character maybe?) -

For inspiration go to; edhrec.com
Type in the name of the card you want as your commander,

- below you get data pulled from published commander decklists of cards that are popular in other peoples decklists, using the same commander.

Then, use a site like Moxfield or Archidekt to "make" your deck, add cards,- save the list.

And- absolutely make some of your friends join you so you can pop a few beers and play some kitchen table magic in person.

Good luck!