You should have a data file for each sensor you collected data from. The file name should contain the time your started sampling and the sensor type you collected data from.
An example data file is shown below in Figure 6.5. The data below was taken from a temperature sensor sampling every 10 minutes. The columns shown the sample number, the time, the ROM_ID (this is useful if you have multiple temperature sensors attached so you can distinguish between them) and the temperature collected (in Celsius).
To look for patterns, you can use this data to create a graph of temperature over time.