I am confused a little bit, need help

I am coming from interspire newsletter and I want to switch to mautic.
I want to create email lists for several websites. Very simple.

But in mautic I see companies section, is that what I need to use, different company for each website email list?

How to easily create several email lists for each website I own.
SHould each website be under new category? How does it work?

I dropped you a line in the other thread, sorry I wasn’t aware that you just switched to Mautic.
First of all: there are no lists, there are segments. Each contact can be member of multiple segments. You can also have multiple users, who can each be the owners of certain contacts.
My solution:
Your websites should have each different account. When you import your lists in csv choose the website’s account as owner of those contacts you import. I suggest you also add a tag during the import ‘source_webisite_A’. This makes it easy to create the segment (or list if you will) for your sending.
Once you imported your lists in csv (owner set, tag set) create the segment by filtering for the specific tag you set.
Than go to Settings - Configuration - Email settings. Set ‘Mailer is the owner’ as yes. Now each email will have the owner as sender (name and email).

Now you are ready to send out your segment email to your list.

why do i need to import tag? Cause I have to login into each user account before sending, so the websites / segmenets will be totally separated…I do not understand
I came from mighty interspire, where I had one account and 10 lists for 10 different websites…so this is bad that I will need to login and loug into each account all the time to check / send stuff…

You don’t need to import tags. You have to tag imports.
You can have 10 accounts with 10 segments, each segment with different owner.
You don’t have to log in each time. I never mentioned logins.