Hi there,
Before I get down to the whole bid, I should probably suggest you to not use Zoho.
I used it when I was first starting up my own business, and while the cost was appealing at the time, I found the features I really wanted were ad-don's, and in turn cost more money.
Id really just suggest getting an Office 365 business account and then you have the Azure cloud to back up to, and pretty much have every tool you need including some automation features with Microsoft Flow.
Enough about trying to change your mind!
As I stated, I did pretty much what you want prior for myself.
I have set up my MX records and all the rest on my Domain host and pointed them to ZOHO's servers etc.
Note the deliver time isn't really three days, its more like a few hours when I have some spare time in between jobs.
I just put that in for timezone differences if your available for Skype or want me to walk through with you what I'm doing, as I'm doing it.
Otherwise if you just wanted it to all work and didn't mind, I would require login information, not only on Zoho, but also your Domain host to modify your DNS/MX records, and also insert a DIKM key for email authentication, it has a generation tool inside Zoho admin control area.
If your interested, feel free to reach out first.
Otherwise again, Id suggest having another look around for a potential better suite for your needs!
As for the SEO on the webpage, I'd like to know how you made it so I can delve into it.
Kindest regards,
Andrew