How to properly implement using CEFSHARP?

Question

C++ / C#

Hello. There is a site where you need to fill in the fields, as soon as you substitute a value, a selection appears in which you choose a more accurate value, etc. in every field. How do I know that the page is fully loaded, then when I entered the first data, then again I find out that the page is fully loaded - just if you insert the values ​​\u200b\u200bin ahead of time, we will get an error or not select the data. ((( THANK YOU