Please help get this MX setup right

I recently transferred a domain (first time I have done this) from Crazy Domains to Digital Ocean. We have 10 mailboxes back on Crazy Domains which now don’t work. When I spoke to Crazy Domain they told me I need to add the MX Records to Digital Ocean, however so far I have failed to get this right.

Crazy Domains gave me: MX Record: mail.myurl.com MX A Record: ip.ip.ip.ip

I have tried adding them on the existing DNS entry for myurl.com A mail ip.ip.ip.ip MX 1 mail.myurl.com.

I have also tried adding a new DNS entry starting with mail.myurl.com A mail ip.ip.ip.ip MX 1 mail.myurl.com (I have also tried 5 and 10 for the priority)

Questions:

1. Should I be adding the MX records on the existing DNS entry for myurl.com or as a new one?
2. If a new entry, should that entry also include the three NS (ns1.digitalo… etc)
3. Priority 1, 5, 10 or maybe all three?
4. Am I right to assume that outlook config stays the same?

Any help will be greatly appreciated. My support guy is away for a couple of days and I would like to get the mailboxes working again if possible :)