In Canada the federation buys a licencee for Swiss Sys. which any TD can use for free as long as they are a member not sure in your country thou!
Demo video didn't show any way to enter ratings, so rather go with pairing cards depending on time between rounds
Demo video didn't shoe but there is a way to ad rating. It is under setings-when you add a new player
ChessManager is a web browser-based solution that runs on any device - it's free and very easy to use (even if it's your first tournament)
Another free online chess tournament pairing program (FIDE approved) is Tornelo. https://tornelo.com/
Try this https://vesus.org/ to manage subscriptions and share final standings. It's totally free and with a modern graphic 
Our club uses Chess Nut. It is the only free offering that I'm aware of that fully supports the USCF requirements and tournament upload standard. It is very intuitive and also web based so no operating system requirements (like SwissSys) and no local file systems which get finicky.
Hello,
here is another program www.vegachess.com . Free under Linux, and freeware up 20 players under Windows and MacOs (run natively under this operative systems).
It support even USCF. Moreover it offers possibility to publish online the results and manage subscription for team tournament and individual tournament as well (www.vegaresult.com).
Who is good arbiter to check this program? I want to make a tournament.
https://swissonlinetournament.com/