I want to forecast time series model

Hello..

I want to forecast time series model.

First, below code is example.

In this code, How can i control ar code? & What is mean ar?

data = iddata(sin(0.1*[1:100])',[]);
plot(data)
sys = ar(data,2);
K = 100;
p = forecast(sys,data,K);
plot(data,'b',p,'r'), legend('measured','forecasted')

But I tried coding using the code above, I failed..(below code is that i tried code...)

I don't know from third sentence to fifth sentence.

data =  iddata(g_Fresult_data_4{1,1}(:,3),[]) ;
plot(data) ;
sys = ar(data,2);
K = 98 ;
p = forecast(sys,data,K);
plot(data,'b',p,'r'), legend('measured','forecasted')

In below attached pictures are what I control file.

I should be the forecast for each row.

In example.xlsx First row is (Wind direction, Wind speed, Exterior Temperature, Humidity,Horizontal Insolation,...)

In example_2.xlsx is Solar Energy Output data.

I would like to forecast a value of example.xlsx and sxample_2.xlsx to the machine learning of the past data.

For example in example.xlsx (horizontal Insolation) & example_2.xlsx (Solar Energy Output)

I want to forecast data aas the relationship between two data.

Although the beginning of the article, please answer.