If you look on skyvector, you can see that Weston is in the class C, and flights requiring air traffic control services do need to file a VFR flight plan (ref Ireland AIP) so you will be filing to get in/out of there. Undoubtedly you can ask/will be shown how to file to depart from there as part of the checkout. Not daunting, same as filing a VFR flight plan anywhere else, nothing to be concerned about. Inismore is in uncontrolled airspace.
If you really want to study the detail it is here, but am sure the reality is a web page on a computer in flight briefing to put in the relevant details. Don't forget to close it on landing at an uncontrolled airport.
http://iaip.iaa.ie/iaip/Published%20...NR_1_10_EN.pdf
When flying in any strange country a read of their AIP is often useful. Many countries have a VFR flight guide within it. In this case the AIP is here
Frame1
and the ENR1.2 VFR rules section will be of use.
hope that helps