Question for sql 2017 standard

1. For Limitations on BAG

"Support for one availability database."

what is this meaning?

I can only create 1 BAG?

in 2016, it can create multiple BAG using 2 sql server.

2. For Licenses included in this edition.

how many server i can built?

how many user ?

3. For Licenses CAL count method.

if i have a sql server.

Multiple device and instance connect to this sql server ( for example 50 devices)

all of it are using same 2 account : for example "sa" and "UserCreatedAdminAccount"

will it count as 2 client?

so that i need 2 cal, right?

(I have checked the licence pdf, still dont understand this)

4. I am using window server 2012 standard, i check online that some of the article said only support 2012 RTM.

But in above store link, it said it support Windows: Windows Server 2012, Windows Server 2012 R2

So my window server can or can't be supported?

5.(sql-server/sql-server-2017-pricing)

Regarding the standard core base licence, is this mean i pay $3717, i will get a 4 core licence?

or i need to pay $3717*2 at least

Thank you