bash - How do I source a shell script for Node Version Manager?

Hi and thanks for looking!

I am new to Linux/Ubuntu, but I have set up an Ubuntu box on which to run Node.js.
I have had moderate success, but now I need to be able to easily upgrade my version of Node.
Many folks recommend using Node Version Manager.
I followed the directions, but when I try to do something like this:

nvm ls

I get a messaging stating that

No command NVM found

I have gone back to check the steps I followed to install NVM, but there is one part that is tricky for may and I think to be the culprit: sourcing the file for bash.

From the instructions:

To activate nvm, you need to source it from your bash shell

. ~/nvm/nvm.sh

I always add this line to my ~/.bashrc or ~/.profile
file to have it automatically sources upon login. Often I also put in
a line to use a specific version of node.
So which file should I add this to? I am guessing profile since it's Ubuntu?

Also, where in the file do I add this line? After I have added this line, do I need to reboot or anything?

Any help would be deeply appreciated--especially if you can show me an example profile file with . ~/nvm/nvm.sh integrated so that I can see usage.

Thanks,

Matt