Your best starting point is to build a User manually in System Manager, then Export that User. You will then have nearly all the information ready to copy-paste for each additional user.
Some other things to consider:
User Provisioning Rules, Phone and Agent Templates are your friend so you don't have to cut and paste everything.
If you have a spreadsheet with columns of "first name", "Last Name", "Extension", and "Email Address" then you can pretty much go populate everything in the import file.
Create a 4th column and concatenate the Email Address with a Profile Name "#Primary". This will be used to identify components on different tabs.
Fields that are Required for SIP Endpoints
Basic Tab
[ul]
[li]Last Name[/li]
[li]First Name[/li]
[li]Login (I typically assign the user's corporate email address - user@company.com since it must be unique. You can also use [extension]@domain.com)[/li]
[li]Communication Password (used for phone login)[/li]
[/ul]
Profile Set Tab
[ul]
[li]Login Name (same from Basic Tab)[/li]
[li]Name (Name of the Profile. If only one, use "Primary". Additional Profiles are optional - "AgentID", for example)[/li]
[li]Is Default (true for the Primary Profile. Additional profiles would be "false")[/li]
[/ul]
Handle Tab
[ul]
[li]Login name (This becomes the Login (email address) with #[profile name] - user@company.com#Primary)[/li]
[li]Handle (SIP Handle - extension or E.164, used to log in the SIP phone)[/li]
[li]Type (SIP or E.164, usually)[/li]
[li]Domain (company's SIP domain - company.com)[/li]
[/ul]
Session Manager Profile Tab
Just about everything is required except for Conference Factory Set and Survivability Server, but fill those in if your system has them.
CM Endpoint Profile Tab
[ul]
[li]Login Name (user@company.com/#Primary)[/li]
[li]Type (CM)[/li]
[li]System (CM Name in System Manager)[/li]
[li]Use Existing Endpoint (false. Set true only if the Station exists in CM but not assigned to a user)[/li]
[li]Extension (same as used in the Handle)[/li]
[li]Template (If you created a template all other fields will be populated based on the template. Otherwise, you'll need to fill in the remaining columns)[/li]
[/ul]
This should be enough to get you started. You can fill out other Tabs as necessary but again, Export a User that is exactly the way you want it to get a starting point.