environment alias name for server name

sql server 2012 when i login as below it shows some values which are unclear to me under server name

how to make sure to put server names some meaningful names to understand

instead of say
CXXXXX1234.xy.LMP.com,99999
i like to give alias name like
Production Database
or
System Test
etc

so that i do not need to refer every time when i login to check documentation to see where i am making changes etc

also how to connect multiple environments same time paralleled like production and System Test, integration etc
do i need to open microsoft sql mgmt tool multiple times or can i open separate tabs in one instance one underneath other?
Where can i refer for good usage tips and learning? any good vidoes or resources around this

what is difference between
windows authentication
and
sql server authentication
when to use which one

please advise
SQLServer2012_NAmeEnv.png