Time to wake up.
In English we say early to bed and early to rise makes a man healthy, wealthy and wise. It’s equal to the Chinese saying 早睡早起身体好 Zǎoshuì zǎoqǐ shēntǐ hǎo.
该 gāi , should.
起床 qǐchuáng , get up or get out of bed.
了 le, a particle here.
该起床了. Time to wake up.

The morning air is really good.
早上 zǎoshang, morning.
空气 kōngqì, air.
真 zhēn, really. It’s an adverb.
好 hǎo, good.
早上的空气真好! The morning air is really good.

Let us take a walk.
我们 wǒmen, we.
去 qù, go, the fourth tone.
散散步 sànsan bù, have a walk.
In Chinese some verbs can be repeated, indicating doing something with relaxation. Here "散散步 sànsan bù" is in line with this.
我们去散散步吧. Let us take a walk.

I come here every day.
我 wǒ, I.
天天 tiāntiān, every day.
都 dōu, means all.
来 lái, come.
我天天都来. I come here every day.