Stuck in milestone 1... cannot understand memory usage

Stuck in milestone 1…I cannot understand what process should I observe…I have tried htop and ps both…In the case of memory usage, it is decreasing after each download-upload…Am I on the right path ?
Please give some clues

check here: https://www.qualitestgroup.com/resources/knowledge-center/how-to-guide/find-physical-memory-available-system-command-line/