You mentioned that you first wanted to try to simply acquire and graph voltage and that once you are able to do that, then you want to try setting up the triggers to start and stop the acquisition.
For the first part, I think that reddog was right, you are going to want to take a look at some of the shipping examples. Of particular interest is Cont Acq&Graph Voltage-Int Clk found in Browse >> Hardware Input and Output >> DAQmx >> Analog Measurements >> Voltage
If you would like to have the time displayed on the X-Axis you could change the DAQmx Read VI from being "Analog 2D DBL NChan NSamp" to "Analog 1D Wfm NChan NSamp". That would make everything be in the waveform datatype which has timestamps included by default.
To address multiple channels simply click on the drop down arrow for the "Physical Channel" control and click on browse. You can then easily select multiple channels by using the shift or ctrl button and clicking the desired channels. Or you can simply change the channel string from "Dev1/ai0" to "Dev1/ai0:4".
For the actual application with start and stop triggering the first example posted does an excellent job of exactly what you described. Just keep in mind that the TTL pulse is high by default, so you will most likely want to look at the falling edges. If you want the same line to be both the start and stop trigger then set those appropriately before starting the acquisition.
Keep in mind too that if you can simply create a task in MAX, then you can always generate the code for your working task by creating a new VI, placing a DAQmx Task Name control on the front panel and select your task then right click > Generate Code > Configuration and Example.
