I'd be very grateful if you could correct my essay

Winter is finally beated (beaten back / defeated ) by Spring finally,. It is a warm, and cloudless, a nice day today.I am sitting beside the window, enjoying the sunshine. And Outside the window, many plants flowers, and girls are taking photos beside flower trees. Children are laughing and playing, chasing each other in the lawn. The dogs are napping off with listlessness.
I will be very gratful if you could correct my essay.

1. you could also say: winter is beaten back by spring, finally. but you need the comma.

2. You are saying: it is a XXX, YYY, and ZZZ. You only need the and at the last position.

3. You should avoid using 'and' at the beginning of a sentence. If you do, it makes the sentence feel very fast and rhythmic. In this case I think it sounds better without the and.

4. plants flower* (you drop the 's' if the subject is plural, like: birds sing, a bird sings)

5. 'flower trees' isn't commonly said, even if it's right. you could say flowering trees, trees covered in flowers.

6. listlessness is a relatively advanced word. your essay sounds very calm and relaxed, and the word feels out of place.

overall, very good. you have a very nice style of writing. I like your calm descriptions of nature. you might like Hemingway or Pablo Neruda if you are looking for something to read.

I'd be very grateful if you could correct my essay. Thanks

__ two spaces

Finally, Winter is beaten back by Spring. finally, It is A nice warm, and cloudless, a nice day today.__I am now sitting beside by the window, enjoying the sunshine. And outside the window, many plants, flowers, and girls are taking photos beside by the flowering trees.__Children are laughing and playing, chasing each other on the lawn. and the dogs are sleeping with dreams of their own - perhaps chasing cats up a tree. napping off with listlessness. [What you wrote is not grammatically wrong.  However, you are painting a picture in idyllness.  Then comes an adjective of listlessness constrasting the entire imagery.  Since this is the concluding line, this does not work well for it makes the reader wondering and dangling in the air.  This way, it gives closure.]

I will be very grateful if you could correct my essay.