How we use "apply & edit chain"?

First of all I would like to say that my English no so good (if my questions are not clear) and that I don’ t know alot about Audacity.
Anyway somebody created an internet radio and I play music for friends from time to time. My problem was that I had folders with 20 or more songs (MP3) and there were playing in my station (with winamp) one after the other but as you understand each song was starting with a delay of 2, 3, 4 , 5 seconds etc. I asked my nephew (he knows much more about these things), how we can fix this and he arranged something with Audacity 2 via apply chain and we fixed 3-4 folders (exporting them to Flac - he said it’ s better).
Now I have another problem. Each sond starts immediately after the previous one ends and I don’ t like it. I would prefer to have a lets say 2 seconds interval between songs. HOW CAN I DO THIS?
I load 2 pictures of my nephew’ s arrangements (he serves at the army now and I can’ t contact him) in order to tell me if and how I can change parameters in order to make this 2 seconds interval.
His arrangements (Tell me if I can change something here):
and how I export the folder with the various files:

Sorry for my long post, George

You may need to raise the “Threshold” level in the Truncate Silence effect. See here for more information:

I’d suggest that you manually try out the settings in Truncate Silence on one or two of the audio tracks before using those settings in the Chain.
If the Threshold is set too high (small number) then quiet sounds may be affected. If the Threshold is too low (big number) then there may be too much background noise for “silence” to be detected. At -80 dB the only audio that will be affected will be near to “absolute silence” and any “silence” that has a bit of hiss or other noise will be counted as “not silent”.

Thanks Steve for your quick reply. I know that 9/10 replies can be found in FAQ but would be taking me alot of time since new here.
I will use the info from the link you posted and hope I ll manage to find a solution. Thanks again,