It all depends on how complex your client's setup is.  It may be as simple as these dividends coming from US-listed shares/ADR and being reported on a 1099-DIV.

FBAR and FATCA (Form 8938) are relative straight forward.  You should be able to understand the requirements by reading the filing instructions and IRS pubs.

For more complex issues, there is not one single source you can go to.  You will need to piece together many different code sections, regulations, Rev. Proc., etc.  CPE courses in this area also tend not to be comprehensive, partly because the law is expansive - and part of which actually lacks clear IRS guidance.

Basic questions are: Is the dividend from a CFC?  If so, is your client a 10% shareholder, officer or director?  If not, are these publicly traded securities?  If so, are these foreign mutual funds, REIT, or similar types of investments?  Are these securities listed on the US exchange or are these ADR?  If not, in which country were these shares issued?  Are these shares held in a trading account overseas?  Did your client reside in a foreign country during 2019?   Did you find out what the maximum aggregate balance and value of your client's foreign bank and financial accounts as well as foreign financial assets were?