If you’re not sure about your MX records, you can use an MX record lookup tool, like https://mxtoolbox.com/. If the settings detected by the lookup tool match what your email provider has told you to configure, then all is good.
Other MX records only the page only apply to MX records that are for the same domain name. So an MX record for any other domains on the account, are irrelevant for the domain you’re trying to configure.