The following is an instructable type article, it is not meant to be done outside of laboratory conditions or under strict supervision with solid safety conditions in effect. I would suggest using cement pads/concrete bricks to use as a base and surround it. Have a water hose on hand and a type ABC dry or D if you can get one. Always wear welding gloves at a minimum, I prefer Kevlar gloves and a Kevlar/Wool working apron. Also use goggles under a full face shield.
Otherwise, honestly, dont be an idiot. Use common sense, and if you dont understand what common sense is, good luck.
After several months of testing various combinations for thermite, a solid easily lit one consists of equal parts iron oxide (red or black- I prefer red) aluminum dust 30 micron/mesh is amazing and works great- add approximately 1/3 the total, unless looking at using large amounts over a liter at a time, in yellow powdered sulfur. For extra cutting power and higher temperatures you can also add between 1/4 and 1/2 the total in potassium permangenate as well.
Lighting this mixture can be achieved with a match, though I prefer making a fuse by crumbling two standard sparklers, making the flakes very small, into dust, encapsulating a regular cannon fuse or electrical model rocket fuse with the dust from sparklers- use paper/plastic or my favorite discarded 7.62×51/5.56×45 or similar cartridges. Crimp top of case, leave primer pocket open.
Place fuse about halfway into thermite mixture, I use 12 centimeters of cannon fuse, it burns about 6 seconds. I prefer electrical ignition, however, there are times when that simply won’t work and besides, lighting a fuse is so darn fun!
I use a variety of containment devices, this is up too you. Remember, thermite is legal as long as it isnt used for destructive purposes, it can be used for welding, cutting or starting wet wood fires. Old pill bottles work great.
Test carefully, it burns hot enough to remove limbs easily! And it wouldnt be pleasant, so be careful. In fact, dont do it. Just watch cool videos of others and enjoy them.
Free the mind and the body will follow