Today I subscribed to a free company email account with Zoho and I set up the CNAME, the MX, the MX2, but I still can't send or receive email from other mail providers - except within my Zoho company adresses.

Zoho asks me to set up the SPF and DKIM in Hostgator and I have no idea how to do it well. I already did everything except the DKIM.

Could it be possible to have a detailed tutorial please ?