First, check the door switch for continuity and proper function. Typically, in newer models, the washer won't fill up with water if it thinks the door is open. This is especially true for front load models. However, this is a common failure point, and I have seen models that allow the door to be opened during fill, but won't agitate until the door is closed. Here is a video of someone accessing and replacing a door switch on a LG model: https://www.youtube.com/watch?v=ip9MhqNK..., and here is a good overview of door switch function https://www.youtube.com/watch?v=o4oKWR9d....
Next, try to get the stored error code. With the machine turned one and door closed, set the programme selector to anything but the first one. Then press and hold the Prewash and Stain buttons at the same time. While holding them, the "End" light will flash a number of times, and then the "Start" light will flash. For example, the End will flash 5 times and Start will flash once, which will correspond to error code E51. You can look this up online along with your model number. If you provide me with your model and/or product number (see sticker inside door recess) along with the number of flashes, we can help you look at the specific error of your washer.
Other things that you can look at for this type of problem:
- Unplug the washer, and wait 5-10 minutes before plugging back in.
- Check the drive belt
- Check the drive motor for proper operation
- Check wiring harnesses and plug connectors to the motor for damage/continuity.
No, you do not press the Start/Pause button. Press and hold the "Prewash" and the "Stain" buttons only. By "hold" I mean to keep the prewash and stain buttons pressed down. Below is a picture with the two buttons you should press and hold highlighted with a red box.
As for where to set the Programme Selector... The instructions aren't clear. I would start at the "60" under Cottons/Linen (highlighted with a blue arrow below) and try there first. If you don't get the flashing lights when you hold down the prewash and stain buttons, I would rotate the Programme Selector to different settings until you get the flashing lights as I describe above.