Hi, I have a question about using AutoCad Architecture desktop.

There are existing drawings (not made by me) that I want to copy to use as my template, but for some reason I couldn't select those lines as if it's somehow locked. But when I looked at the layers, it was unlocked. And interestingly enough, I could still snap onto those existing lines to draw over it. But that takes time, so I was wondering if there is some way to unlock it and  select those lines.

thanks for all the help.