I am having a hard time to set up Mission Planner

What brand/model is your phone?
Right now you need to set up your RPI unit before doing anything els

Actually I do not know what is RPI Unit.

I have iPhone 6 and Samsung Galaxy J7. So IOS and Android.

RPI = Your Raspberry PI
Ok, could you install Fing app on one of your phones?
Fing https://www.fing.io/

Alright wait a moment… 10 minutes…

I just got that app…

1.Turn on your RPI and have it connect to wifi (as you mention earlier above)
2.Connect your phone with the Fing app to the same wifi
3.Run Fing app and look for a device named Navio and let us know what IP address it has.

I got Raspberry Pi but not navio…

Where is your Navio then?

I cannot find it…

OK, when you find it let us know and we can progress with the installation.
You can not do anything without it.

Actually IP of Raspberry Pi is navio, because I can find navio.local on same IP from laptop , but I cannot find navio in same IP from my galaxy phone but found Raspberry Pi on same IP.

Post a picture of your Raspberry PI, please

What information do you need?
What do I take a picture of?

Fing result

Generic. Raspberry Pi
10.x.x.x. 38:xx:xx:xx:xxc

Need a picture of your Raspberry PI device.
To see if you have a Navio mounted on it

I am sorry, I just went to bed because of tiredness… it was almost 4 AM. I went to bed at 2 - 3 AM for last 3 days. That was my mom who answer for the last two replies, she went to bed earlier than me. I will post it after school ends. But, what fing is for?

Fing displays the ip address you need later for setting up the navio and connect misson planner to

Alright, I will expect a good result.
Can you be with me after 7 hours from now?

7 hours from now would be 0100 at night here. But you might have luck having somebody els answering your questions in this thread

oh okay, but how were you able to answer at 4 AM, wasn’t at 9 in your location?

Yup. I am up usually around 0600