In this video, Pye from slrlounge looks at everything you need to know about off-camera remotes and how to set them up correctly.
The first tip is to turn on the wireless radio – every wireless RF system will have this option – just make sure that this is on and not the optical or infrared.
The next tip is setting up the channel of the flash and the remote on the same channel otherwise they will not work together.
Now you need to set up the groups that will allow you to set up and flash a number of flashes in the same channel and give each of them a different power level etc. For example, you can set you key to group A, your fill to group B etc.
Now we need to talk about manual and Through The Lens (TTL). Pye suggests that you stick to the manual so that you will have full control over the exposure level of your flash (TTL allows the flash to take a reading and give a suggestion of a power level so a sort of auto mode).
The next option is divided into three options: you have first curtain sync (FCS), second curtain sync (RCS) and High-speed sync (HSS). The FCS function fires the flash when the shutter is opening, RCS fires the flash when the shutter closes – this is important in long exposures. HSS allows you to shoot in over the 1/200 or so that your camera flash sync speed allows you to shoot at naturally (in most flashes this will only work in reduced power output).
Finally, you have the power settings. Each manufacturer has this in a different way. Profoto simply has a single number of 10=100%, 9=50% of the power. In other flashes, you might have 1/1, 1/2 etc. each is basically one-stop more or less light (and you can of course increase or decrease the power level by less (or more) than a stop each time.
These are the basics – there is of course much more but understanding these preliminary settings will allow you to start working with flashes and experiment with what they can do.