In order to include your husband on your return, you would just add his information to your return and add his personal information with yours at the beginning of the return.
You will need to change your filing status to married filing joint. When adapting a separate return to a joint return, you will probably remain the 1st taxpayer on the return.
If you want to file joint and have him be the primary taxpayer on a joint return, then you may need to create a new account, add him first and then add your information.