You will need aida cloth or other fabric fit for cross stitch. The size of the image in the end will depend on your type of cloth and how far apart the holes in it are. I used a 7 aida cloth. In the end I find it a bit too small, but meh.
You will need 4 colours of embroidery floss, here are the ones I used :
Black : DMC 310
Dark green : DMC 895
Light green : DMC 3346
Red : DMC 817
You will need carbon paper to transfer the elder sign on the fabric. An embroidery hoop and a small screwdriver will be very helpful but you may do it without hoop (if you use a hoop though, you will need a screwdriver). I prefer wooden ones to elastic plastic ones.
You will obviously need scissors and a needle (embroidery needles are usually bigger and less sharp than sewing needles, and their eye is bigger).
You may find all of the above in a fabric shop.
In the end you will need a frame, but you should wait until the cross stitch is finish to take the measures.