Support/Resistance are not trade signals...they are an analysis or simply referred to as "s/r analysis".
Thus, you need a trade signal (e.g. traditional chart patterns) to use with s/r analysis. For example, if your chart pattern shows up at a support area...your chart pattern will give you either a buy or sell signal. Yet, if no trade signal appears when price reaches support...there's no trade.
Newbie mistake is to think that support implies only buy and resistance implies only sell.
Same is true for resistance.
How do you determine them ? Use Google...there you'll find maybe many dozens of different ways to compute s/r levels and you'll find hundreds of trade signals on Google to use with s/r levels.
Also, most of today's charting software have s/r analysis (several types) computed in the software.
Simply, S/R Analysis is one of the most commonly discussed analysis on the planet. Very easy to find all the free info you want on Google about any questions you have about that type of analysis.
By the way, if you hate Google...use the "Search..." function here at the forum in the upper right corner. You can find maybe a few hundred threads at this forum where members talk about their use of s/r levels (analysis).