Hi,
I don't think its quite as easy as is being made out.
Often you won't find the chords in which case you need to learn to work out the chords for yourself - can be done if you have the tune, some chord theory and some time.
If stuck then it is worth posting requests for chords for specific tunes on this forum. I have posted several requests for chords over the last few years and sometimes I have got them and sometimes I have not.
There are some threads in the database on chord theory that you can search through that may help.