I'm not sure where the missing instructions are, but you can find the address to mail your federal tax return on the last page of the instructions to Form 1040. You should sign and date your federal return and attach copies of W-2 forms and any other forms that report taxes withheld to the return.
For your state return do the same. The address to mail your state return may be listed on the tax return, normally near where you sign it. If not, you can look up your state department of revenue online and there should be an address listed there where you can mail the return.