Freezing top x lines in a table

[Bruno Baumgärtner <bruno13 wossc org>]

Hello
I am in train to leave LibreOffice as this Methuselah is aeons to large for me. I 
need a simple calculation program to follow a few sales figures.

I have imported one of these files from Calc and all works well. But I can not 
freeze the first 6 lines like I do up to now. I am using Kubuntu 14-04 and will 
change to 18.04, the next LTS.

Could someone mail me the way, please. Would be much appreciated.

Extra question: Are you having a live chat group?