Can you post the model number please.
Number on top of door - SGS5358GB/17
Ok if its not draining what you need to do is first check the drain hose. If it goes under a sink then remove the spigot it pushes onto and make sure that's all clear.
Then if that's fine you need to remove the bottom basket and scoop the water out.
From there remove the filter and the mesh filter.
There in the sump on the left at the bottom is a cover. Remove the screw it will be a torx screw (star shapped) and then remove that cover.
There you will see the pump impeller. Make sure the pump impeller is all clear from obstruction.
Then refit the cover and retry the dishwasher and see how it goes from there.
If its still the same and not draining then you may find the pump is at fault here.
If you need anymore info just get back to me.
No idea how to check the drain hose or what a spigot is - is this a job for a plumber?
Not really. Is the dishwasher next to a sink?
If so just look under the sink and if it has a spigot then you will see the drain hose pushed on to it. Just pull the hose off and unscrew the sink spigot and check it from there.
But if it isn't next to a sink then its problery going into a standpipe behind the dishwasher which in this case the drain hose will proberbly be clear.