Network Audio Player - need some basic advice

I am a bit of a Marantz fanboy and currently listen to mostly vinyl and cd's.  I have over 500 of each and never seem to be short of listening options. I use a Marantz PM-11S3 integrated amp and an SA-8004 SACD player.

This weekend my boys pressed me on why I cannot access music online.  Being an old fart, I had no response other than to offer to play them some of my vinyl.

Shamed by my spawn, I tried to read up on what was offered by Marantz in this category.  With at least  four products (NA-6005; NA-8005; NA-11S1; HD DAC-1) spanning in price from $649 to $3,499, I quickly realized I had no idea what the basic selection criteria should be - there are so many formats I am unfamiliar with as well as a variety of input connections.  In addition, I am quite concerned about the obsolescence factor given how rapidly these formats seem to change.  I also do not understand why some have wireless connectivity and some do not and whether this is a big deal or not as my system is on a different floor than my incoming service.

 My SA-8004 has a USB port on the front and coax and optical inputs /outputs on the rear, plus an input labeled "USB DAC" which is an unusual shaped input unlike the usb on the front panel. The PM-11S3 only has RCA inputs.

Can someone give me ( or point me to) a basic primer on this topic? What are the essential features to look for?  I am a complete luddite, so it needs to be REALLY basic, i.e. the more acronyms used, the more my ears begin to bleed.

I love my other Marantz gear, and start with a bias towards the brand , but are they offering a good product line for this, or are they behind the curve.  If not Marantz, then what does more for the same money?  If I cannot plug directly into my internet connection, is there a device I can buy to make a wireless connection?

Given my preference for vinyl and cd's, I do not want to spend a ton of money for another piece of gear, especially if it will be obsolete in a year or two.

Thanks in advance for any guidance you can provide.