창문으로 밖을 보고 있어요

지금 창문으로 밖을 보고 있어요.

보다 is transitive. You use it with an object (as opposed to with 로. If you use X로 보다, it means you're watching/looking at/seeing something *with* X).

So you can say something like this:
창문 밖을 보다 (there is an omitted 의 after 창문, so it's "look out the window" lit. look at the window's outside)
창문 너머를 보다 (there is again an omitted 의 after 창문. 너머 is a noun meaning "across" so it's "look through the window" lit. look at the window's across)
창문을 보다 (this is just "look at the window")

정원을 볼 수 있어이 보여요.

볼 수 있다 is more "can see" as in not blind, or "can look at/watch."
To say "I can see ~" as in there's something in your field of sight, you use ~가 보이다.

정원에는 꽃과 식물이 많아요.

Don't forget your particles! Dropping particles is a fine art that takes a lot of practice. First, you need to learn how to use all the correct particles without dropping them.

우리저희 집 근처에는 작은 거리가 있어요

저희 - ~어요 politeness match
Again, particles.

거리에서는 아이들을이 놀 고 있어요.

You don't space 고.
In "The kids are playing," the kids are the subject not the object. As such, you'd use 이 not 을.

그들은 자전거를 탄타는 중이에요.

-ㄴ would be past tense.

오늘은 일이 너무 바쁜 일이예빠요.

저는 그 아이들을하고 자전거를 타러 우리서 저희 집을 떠나 고 싶어요.

Why the 을 before 하고? 저 <-> 저희 politeness match. No space before 고.
타러 is "in order to ride," which doesn't really make sense here. Perhaps you meant 타서?