Cannot use the storage on my phone

[nice.skin.boss007]

Hi,
Apparently I only have 2 gb of free space on my phone. I was shocked, because I have 32 gb of storage, so I investigated. I have used 20 gb including the OS. So why does it say that I only have 2 gb? I have a huaweii
P10 lite 2017. Thanks
Update
I have that 10 gb are occupied by "other". What is this other and how can I get rid of it?

 

[Scottray]

Download CCleaner from Google Play store. Run it and pick the options to clean out the junk that you don't want.