Q:

How do I connect my iMac to a Windows SMB share drive

I work in an organization that runs a Windows network of 1000s of computers with Windows 7 installed. We have lots of SMB share drives that store information. My job is a new role for a graphic design area and I've been setup with an iMac. 
Now the problem: This is the only iMac in the organization and I'm not familiar with share drives. I've been told that I've had my "credentials" set up and should be able to connect to an SMB share drive that contains all our fonts, images, and videos.
How do I connect my iMac to this Windows SMB share drive?

A:

This answer assumes a few things:

your iMac is already connected to the network (most likely via ethernet)
that your credentials are all setup (based on your question, they are)
that you’ve been given the host address for the share drive

To connect to the share drive, you should only have to:

Make sure the Finder is active
Press commandK (or, in the top menubar, click on Go and select the Connect to Server… option)
A Connect to Server window will appear with a Server Address field
In this field enter the host address (it should start with smb://)
Click on the Connect button
You should now be connected and able to access all the files via the Finder

Note: - If you’re not already connected to the network, or you require different credentials for this share drive, then after Step 5 you may be prompted to enter your username and password.
[EDIT]
If you do have to enter your username and password, it's likely you will need to enter the username in the form of "DOMAIN\username" where "DOMAIN" is the name of your Active Directory domain. If you're unsure of this, your IT helpdesk should be able to tell you.

A:

Your IT department shouldn't have just abandoned you at this point. They should have worked through it with you.
We can't really answer this without knowing more detail of the network setup there, but the basic premise would be to start from
Finder > Go > Connect to Server...
simply type smb://[address you should have already been given] & hit Enter.
Corporate networking is really beyond the scope of Ask Different & ought to be handled by your own IT team.

