Opensearch dashboard data vizualisation


I am new to opensearch and I am trying to vizualize some data on dashboards.

I am trying to do a simple example. I have an index that I am adding data to it.
Each data have a value field (float) and a date field. I already configured the data types of the index to have these types.

I would like to vizualize the variation of the value with time. When I access the dashboard to do this, I have to use aggregations and I am not understanding which configuration I should use to do this task.

Can someone help me with that.

In addition to that, I am trying to add the following date format : dd/MM/yyyy HH:mm:ss
For example : 14/10/2021 17:04:07
opensearch is considering this value when he parse it : 14/10/2021 15:04:07
There is 2 hours difference. I tried to add a timezone to the date value, but i am having a parse error.

Thank you in advance for your answers.