Essentials, One and Two

Often asked," What size oven do I start with'? That's a hard question. What size family do you have, or what size group are you going to cook for. For the average family I recommend a Deep 10" or a 12". Are you going to cook taller cuts of meat , or just Potatoes, and bean types of things. For a larger family, I would start with a Deep 12". That way you can cook large cuts,and big pots of beans. For your next oven, a regular 12" may be best. a third oven may be a 10", good for all kinds of desserts. The rest is just up to your needs. Available ovens are.
5"
6"
8"
10"
10", deep
12"
12" deep
13"
14"
14"deep
and 16"

There are other sizes of specialty ovens, but you wont need these until you have special needs.

The other thing you need, is a place to set the lid when it is hot. The lid holder, or stand is the place for that. A hot lid will burn the table, and the ground will get it dirty. There are many lid stands of all shapes.  You can even make your own. I have seen them made from  horse shoes, bent and welded in many ways. Even things like a wok ring, or a inverted Stainless steel mixing bowl will work.
A lid stand, with an inverted lid will make a good griddle.

If you have any questions, just ask them in the comments. I will answer them there.