To generate the contours, the following procedure can be followed

Open QGIS of any version available to use. This is an open source free software and hence license is not required to use it.

Ensure that your computer/laptop has an active internet connection while using QGIS as it requires the data to be downloaded.

When the QGIS opens, upload the boundary of the village which is in .kml file format.

The .kml boundary of the village will open in the main page of the QGIS and its layer name will be visible in the layer panel which is to the left of the main window.

Install SRTM Downloader Plugin

Go to Plugins | Manage and Install Plugin. Search for SRTM Downloader

Click Install plugin to start the installation. Once the installation completes, there will be a new menu SRTM Downloader under Plugins.

To use the plugin, click SRTM Downloader and then specify the extent

Go to Raster | Extraction | Contour. The contour creator window will open up. You will need to specify the following:

Input layer– This should be your SRTM imagery, Band number –band1, Interval between contour– type the contour interval you want to generate, Attribute name –field name for the elevation data, Advanced parameters –You can specify the output contour file here. If you leave it blank, QGIS will create a temporary scratch layer.