Step 1: Everything You Need
4 7 foots 1/4 inch steel rods. They will be use to do inserts into the construction. You can get some from a metal vendor. You can also replace this with eyelet screws and stainless wire.
1 4' by 4' 3/4 inch exterior grade plywood sheet for base and top.
16 3/4" by 1/2" Corner braces with 16 1/2" screws.
8 1'1/2" #8 bolts and nuts
2 sets of 70 LED lights.
Step 2: Base Construction
Do a 10 degree (doesn't need perfection) angle at one end of the 3/4 inch rod.
Cut a 30 inches circle. This size can go through an exterior so you can mount the tree indoor. You can cut the inner section too if you want the whole thing to be light weight.
At about 1 inch from the edge, drill evenly 1/4" to 1/2" deep holes to do inserts.
Step 3: Top Construction
Drill evenly from half an inch from the edge to do inserts.
Tip: try get an angle of about 10 degree for each hole. Drill them as deep as you can without traversing the wood piece.
Step 4: Final Assembly
If everything is ok at this point, you can do some painting for top, basement and rods. I painted the steel rods with anti-rust painting.
Once done, remount and mark base rods for drilling with a corner brace. Drill rods and install base corner braces with bolts and screw them to the base. Do the same step with the top section.
The only thing needed are light sets. Display them evenly and attach them with tie wraps.