There is probably no such thing as a single indicator that will give you 100% guarenteed profits all the time, reliably ever day. Also many will state that to use indicators only is not reliable, but price action is the main ‘indicator’ of when to buy and sell.
The main places to learn the indicators is through the babypips school, various free lessons by the brokers. I used the free webinar courses from XM and Forextime. Another free information source is Wikipedia.
I would recommend Moving averages to start with for basic analysis. It is the most common and easiest to understand.
For example; I will use daily moving averages (MAs) of 55 and 200 periods. These give me a very good idea of a trend direction and if there is a trend. For example, currently the MAs are pointing to an up trend in the EURUSD. Should I buy now? No, I need further confirmations. Another tool I use is the ADX. It confirms if there is a trend. Currently it is below 25 (on the daily chart), so I am not trading (In fact the ADX is trendless / ranging for all the majors I trade, therefore I am out of the market / not trading).
So far I am being shown that the EURUSD in in an upwards trend, but that the trend has stopped. Now I wait for confirmation of a new trend before I trade again. Another tool I use is the RSI. If it is in overbought or oversold territory it can warn me of a potential change in direction. Recently it warned of highs at around 1.2 on the EURUSD, this was an excellent time to take profit. Currently it was high and is heading down.
In summary, some indicators indicate when a trend is in action or not, some point in the direction to trade. Other swill warn you when the market is about to turn. Thinking in this rough way, we could look for indicators when a market is about to turn, then look for when a trend is about to begin and finally trade in the direction of the trend when all the indicators line up properly. This is just a rough idea of the potential logic of one way to use different indicators together.
As an example, currently I am not trading as I an getting ranging readings on the daily charts for EURUSD (and other majors). So I wait for other indications that the market has started moving or trending again. There are some indications from the RSI and ADX that when a trend resumes it will be of a weakening EURUSD position.
This is one small example of how I use the technical indicators. There are others I use too, such as the Ichimoku Cloud, Stochastics and basic trend analysis. There are various other techniques I use to actually trigger trades and exit trades when the technical indicators give me the background of what is happening in the markets.