difference between "help to" and "help"

0I'm looking for the different use of "help to" and "help" verb, both of them are followed by infinitive. I don't understand their usage and in my English grammar there are not any definitions. 02br
02br
00When I have to use "help to" and when "help"?02br
02br
00Thanks in advance for your hep!02br
02br
00Valeria0-