In order to accurately test the chemical balance of the water you need a high quality test kit, such as a
TF 100 or a Taylor K2006. We recommend the tests kits since test strips give very inconsistent results and pool store testing is only as good as the person conducting the tests. Pool stores also frequently use kits that cannot test high levels of chlorine that are needed to maintain shock level during the shock process.
Since your pool will be new there likely is no salt in the water. Existing pools should check the salt level before adding salt when they are switching to a SWG since there will be some salt already in the pool from previous chlorine use. You can purchase and use salt test strips to check the salt level periodically.
SWGs are good at maintaining FC levels but are slow building up to the recommended FC levels. You may want to supplement with liquid chlorine to give your SWG time to build up to FC levels.
If your water was clean and clear in your old pool then you were not necessarily doing anything wrong, but you were very fortunate! Keeping the water balanced is not difficult when you give the pool only what it needs.
I hope this answers your question. Good luck with the new pool!