Post a picture of the speakers so we can better guide you.

There are two apps for Sonos speakers. Some of Sonos older speakers will need to use the S1 app and newer speakers and some older ones like the Play1 and 3 can use the S2 app.

Look here to see which speakers work with each app:

https://support.sonos.com/en-us/article/sonos-app-version-compatibility

Not generally, no. It sounds like there has been some setup issues, however. 

Since they were gifted to you, were they ‘new, in box’? Or factory reset to remove the previous owner’s saved data? Doing the latter, if you’ve not yet created a system, might be extremely helpful. 

The speaker information is generally on the label on the bottom of the speaker. It would also be helpful to know which Sonos controller you’re using, S1 (for older speakers) or S2 (which runs most speakers). You may want to read this FAQ , and this thread. 

A while back, there was an issue with one release of the software which seemed to require multiple logins, but to my knowledge, that has been fixed with subsequent releases. Are you certain you’re using the most recent Sonos software on whichever mobile device you’re using?

Normally, you’d want to set up one speaker, then use the ‘add a device’ function in the controller to add a second one. Many people have found it easier to leave the first speaker temporarily wired, if both speakers can run SonosNet (newer speakers can not.). The Ethernet cable should be able to be removed, once the other speakers are set up, assuming your network conforms to the Sonos Network Requirements FAQ.

I would encourage you to call Sonos Support directly to discuss your ongoing concerns, there just isn’t enough detail in your post to supply more specific assistance. 

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Edit: ​@Pools-3015 types more quickly ;)