Could someone please explain what this is?

There's loads you can do. I love landscapes so if I'm stuck on describing a castle then I'll actually go to one and check it out, same for gardens, etc. Take a notepad with you. You could google landscape pictures and then describe them yourself. Stick the words in a thesaurus and write them all down. I'm sure that will help. Read books... I've been through all of the LOTR books on many occasions as J R Tolkien comes up with tons of different words to describe something so simple like the sun or a river. His imagination is incredible. Movies might help too. Watch something and pay attention to the setting. yze everything you see and then later on it will all come naturally to you.