hey all...

I am using auto cad 2018 on my Mac. I am trying to edit the dimensions of my drawings which I have made mistakenly but I am unable to do so. I have been using windows platform earlier and could modify easily by double clicking the dimensions but I don't know about Mac. could you help me to do so? I have attached a pic and file of simple box. let me know how to change 19 to 20 and 10 to 15. I am asking it in simple drawing so that I could change finally in my project files. 

thanks

vishal