You have your new kiln unwrapped. Now where to put it?
First read the manufacturer's recommendations. If you are still uncertain there are a number of things you should think about.
One of these is getting access around it. You need to be able to work around three sides ideally if it is a top loader, two sides for smaller kilns is usually enough. If it is a front loading kiln you only really need to consider the space in front of the kiln. You are going to be carrying pieces, even shelves to the kiln so you need enough space for you and the shelf in front of the kiln. At the sides you only really need enough space for yourself.
Getting access is part of the consideration of distances from other things. Often people are worried about the heat that the kiln will be giving off. Kilns are well insulated to reduce the costs of firing, so the heat release is slow. Still, you want at least 300mm space from anything inflammable.
You also will want to think about the support surfaces. Sometimes the kilns come with their own stands, but usually these are to raise the kiln to working height. You may want to protect against any (unlikely) meltdowns, so you should put the kiln on steel, ceramic or concrete surfaces. There are a number of table top models and in these cases a large ceramic tile or ceramic fibre insulation under the kiln is an entirely adequate safety precaution.
You will need a place to put things down just before loading the kiln, so placing the kiln near adequate flat surfaces is important.
You also should think about putting the kiln out of the main traffic areas of the studio to avoid disturbance to the kiln or the rest of the studio activity.
Now that you have the ideal location for the kiln you have only begun.
You need to make sure the kiln is as level as possible. The first stage of this is to make sure the casing is relatively level. Use of a spirit level on the top front and sides is probably enough. Put hard spacers under the legs to level things up. You can if you want, level the internal base of the kiln instead of the casing. Many find that more re-assuring. Then you need to put the kiln furniture to hold up the kiln shelf into the kiln and the shelf on top of that. This is the part that really needs to be level. Spend time on it. Place pieces of ceramic fibre under the shelf supports as required to get things really level. A circle or three-way level is good for this purpose. The shelf needs to remain level to get good, consistent results. Any time you move the kiln, the shelf, or the supports, you need to check the level of the shelf.
Once you have the shelf level you are ready to do a test fire. Normally you need to have a firing without anything in it to burn out binders used in the making of the kiln. There is no reason that you cannot have the furniture (shelf and supports) in the kiln for this first firing as they need to be test fired too. In addition you can run a test to discover where the cool spots are in your kiln (every kiln has them). Look up and follow this technical note on how to run a test for discovering how even the heat is within your kiln.
Once you have run your test firing, you will want to protect the kiln floor from any spills of hot glass and the glass from sticking to your furniture. If the manufacturer has given you some kiln wash with the kiln mix it up about 1 part powder to 5 parts water and lightly paint the floor of the kiln - not the walls. The kiln furniture needs this too as does the shelf. This note on applying kiln wash will give you information on how to do it.
It is important that you have some protective gear to do the work with kilns. At first and for fusing temperatures, you need eye protection and gloves. You need to look frequently and briefly into the kiln to monitor the firings, especially at the start of your career. For this you need eye protection. Sun glasses will not do as you need protection against infrared rather than UV light. There are a number of things that will do from welders' goggles to special lenses as used by bead makers. Use them! Every time. You will need gloves, at the start leather gloves with sleeves going half way up your forearm (such as welders' gloves) will do. Later and for higher temperature work you will need better and much more expensive gloves, sleeves, and body protection.
These things will get you off to a good start.