While walking home yesterday, I found a discarded fire pit (I initially thought it was a portable grill, but then then realized that it had only a mesh cover). Some details:  it's essentially an iron bowl with no bottom vents the lip is ~23", including the outer rim. ~22" excluding it the grate inside is ~11"  I would like to use this while spending as little money as possible. I assume the biggest downside versus an actual grill is that without a solid cover, I hit lower temperatures, and I'll lose some smoky flavor. Some questions:  Should I get a wider grate that rests on the lip instead? Or can I get by with having a few coals that the small grate can rest on? Should I try to find a solid grill cover instead of the mesh? What would I miss out on if I don't have a cover? Any other equipment I should have to avoid surprises? Is it ok that I don't have any bottom vents? Unfortunately I sold my drill a while ago and don't have access to one right now.  Note that while I cook a lot, I grill very rarely and this will be the first time I grill without someone experienced with me - so I'm not looking to get into anything complicated right away; I'm hoping that this will help me practice some basics.  
If you can find a mesh cover large enough to go over the top that's certainly an option, you need to work out a way to keep it in place, you don't want it sliding around on you. Meat will stick, lifting the meat off when it's stuck will cause shifting if there's nothing holding it in space. Perhaps an easier option would be to get long metal kebab skewers instead of a mesh or slatted grill. If these are long enough they could go the long way across, or they could be placed at an angle from the rim on one side to the body inside. This would give you a lot of flexibility to control the amount of heat each piece of food gets. One solution I've often used for campfire cooking is to place a cast iron frying pan straight on the coals, that would work just fine on your fire pit as well. 