SU priveleges on user account
I am adding a user to my very modest Ubuntu 12.04 system. Currently, there is myself, with administrator priveleges, and one other user.
I am not really very experienced with this sort of thing, but was easily able to set up the new user (call him "James") and get a basic amount of functionality going. I told james what his password would be.
I began to customize this user's account somewhat, and immediately ran into trouble. For example, I tried to install a CHrome extension under the user's account, but it failed, and I would guess that would be because James has no administrator priveleges.
I went to a terminal on his account, logged in as myself (administrator larry) by using su larry, but larry doesn't have any rights writing files in his account either so that didn't work.
What is the most straightforward way for an administrator to install programs in a non-administrator's account given that he knows the users password?
Thanks for your help.
PS. As a matter of fact, I did RTFM. However, I didn't Grok TFM, which is why I am asking this dumb question.