How can I create multiple lines with error bars and a legend?

Hello,

I got three data sets like this:

a=[8,2,3;2,5,2;5,2,4;1,7,4;4,4,5;2,3,3;3,2,6;3,4,5;3,2,4;2,1,3]

The first collum represents the base values, the second the " testing" and the third the "second testing".

I would like to present them as a line with 1x multiplied errorbar and a legend. Like this:

Unfortunately I do not manage to do with

errorbar(a,err)

Could you help me, please?

Thanks.