Config help for small M365 network

I’m reaching out to see if anyone has son general tips on implementing Adam specific to M365 business. Larger shops probably know all the buttons to press but for smaller installs there is little in the guides for connecting to M365. I setup home.arpa thinking it wouldn’t be a problem but service ports like MEM get blocked. Should I be using an onmicrosoft domain? Is there anything else a smaller business should consider they wouldn’t find in the manual. Using the business pro subscription.