Minimized Window or Application not appearing on task bar or panel

i am customizing my desktop, i have accidentally clicked an icon on my panel, (i forgot what was that icon), now, i lost my default panel and task bar, I've added new panel, but the icons present in the default were not there (network, installed devices, clock, battery life, etc.). and also, when i am minimizing programs or windows, it doesn't appear on the new panel that I've created, i have to use ALT + Tab just to navigate to the windows or programs that i minimized. how to get back to the original panel or the task bar???? pls. help!