In you keyboard you have a windows logo key. If you press it the start button on screen will show the start menu.
But there is a combo key’s for shorcut some functions,  here the list:

Win Key + D: Minimize or restore all active windows
Win Key + E: Open windows explorer file manager
Win Key + F: Open file search window
Win Key + CTRL + F: Open computer search on own network
Win Key + F1: show online help for Windows OS
Win Key + R: Open  Run window
Win Key + Break/Pause: Show your System properties window
Win Key + shift + M: Restore all your minimized windows
Win Key + L: Block the current user and request the password
Win Key + U: Open a utiliy manager (magnifer and more)
Win Key + Q: Switch between active users