Compare average

Hi everyone

I'm new with power BI and I'd like to use for forms analysis, I have a survey with 12 points which helps me to evaluate my trainers, So what I'like to do it would be to compare the average of all my trainers vs the average of one of them

So what I've done, I created 12 new measure which calculated the average for my 12 points after that I put my 12 points with the column in a chart where I can tick my trainer's name, the problem is as my values arent group My chart is unreadable

So is it possible to group this values? And could I create a new talbe with new measurement becaue I'd like to create a trend and it isnt possible with my new measures

Many thanks in advance