How to predict future new points in a time series?

Hi all.

Hope you are doing well. I am new to MATLAB.

Right now I want to predict the future points in a time series which are completely missing from a input series.

I found many approach in Matlab community sugggesting to provide the full dataset and then divide it into train and test part which further calculating the predicted value according to that test part.

But my question is however a bit different. I was trying to predict the future or say missing value of a portion within the time series.

Here I'm attaching an image to describe my question,where the blue part is the data I have and want to predict the red part.

Could anyone please help? Any relevant suggession will be great for me to proceed.

Thanks in advance.