gently, quietly

I open the window just a little.

私は窓を少しだけ開けます

I open the window just a little in the bedroom.

私は寝室で窓を少しだけ開けます

I open the window just a little in the bedroom this morning.

私は今朝寝室で窓を少しだけ開けます

I open the window just a little in the bedroom this morning to let in fresh air.

私は今朝寝室で空気を入れ替えるために窓を少しだけ開けます

I open the window just a little with my hand in the bedroom this morning to let in fresh air.

私は今朝寝室で空気を入れ替えるために窓を手で少しだけ開けます