Changing Roman numeral line for positions on guitar

I've seen 1 or 2 short explanations on how to change it but I still don't get it or it just doesn't work for me.
They say the properties panel changes it but all i see for the options are that x and y stuff. Another mentions properties right next to the palettes tab but that is not there at all? The best one states this but I still don't understand
" Place a line titled VII (There is Text Line which features the VII under the Pallet, "Line" which I selected
- Select the line on your score (did that, if that was the right one to put onto the score)
- In the Properties tab, see the panel headed Text line which defaults to the sub-tab Style (I get lost, sub tab, panel line?)
- Switch to the sub-tab titled Text, and change the text to your new III"

Does anyone have a detailed explanation for changing this for Musecore 4? Or a video? Because somehow everyone asking for help can figure it out magically but me, and I would like to be able to combine a roman numeral to a line sometimes rather than just the positions.