Do you want to get up?//بدّك تئومي //بدك تفزي // 

Noticed that you can just say the verb without using( do you need)--->( بدّك )

So it's gonna be like تئومي ؟ 

Do you want to go down?//بدّك تنزلي 

Do you want to help?// بدك تساعديني 

Do you want me to carry you?//بدك احملك 

Share please.( if you mean food sharing )

ضيفيه for boy or ضيفيها for girl 

Play by yourself.// العبي لحالك 

Nap time.وقت القيلولة and also it's OK to say وقت النوم 

Lets take a nap.يلا ناخد قيلولة أو يلا ننام 

Bath time.وقت الحمّام  

You need to take a bath. صار لازمك حمّام او لازم تتحمّمي

Messy.//we say to a messy child ( عفريت او عونطجي )

Do you want to get up? بدك تصحى

Do you want to go down? بدك تنزلى لتحت

Do you want to help? بدك تساعدى

Do you want me to carry you? بدك أشيلك

Share please. شاركينا من فضلك

Play by yourself.ألعبى لحالك

Nap time. وقت الغفوة

Let's take a nap. ياللا ننام شوى

Bath time. وقت الحمام

You need to take a bath. بدك حمام

Messyملخبط

What a mess يااه على الفوضى  I am not sure

Also, if there are other phrases often used with children, please let me know!

شكراً!!

do you want a breakfast? بدك تتروقى