Fire Box Grate

So i am brand new to smoking on a stick burner. I keep having a problem with my coal bed falling through the grate in my firebox with both briquettes and lump charcoal shortly after i begin the cook. So ended up taking out the grate in the firebox and just ended up building my fire at the bottom of the firebox. Was this a rookie mistake to take out the grate? If so how should i keep the bed of hot coals built up on the grate?