Have you reviewed the UKVI guidance on Family Members of Tier 2 (General)visa holders ?

Please look here

Your partner can choose to either accompany you to UK or join you at some later date.

Have you reviewed the UKVI application form ?

Your partner would need to make an online application, however just as an example of the application form details the here is a link to the Points Based System Form (VAF10 Dec 2012) Dependant

Hope that helps you to get started