Trigger

I'm using V6.5.3.

I'm trying to create transaction logs for particular table, so I need to
write trigger on insert/delete/update on each row. Are there any
examples/documents that can help me with this?

In the "Interaction with the Trigger Manager" from the online document,
it states that it's for V7.1 or later. Because I'm working on earlier
version, do I need to modify my code if the database is upgraded to
later versions?

I'm writing the C program in under my home directory. How can I set up
the environment so that my program compiles?

Thanks in advance for any helps and directions.