My starting page was Charlotte's Lively Kitchen - a wonderful resource with a lot of background teaching you the step by step process. This really is an essential read https://charlotteslivelykitchen.com/fondant-filled-chocolates/
Use a 70% chocolate - I like to Lidl's Madagascan 70% single source chocolate
Tempering the chocolate
Read Charlotte's Lively Kitchen. When you've been through it once, the magic numbers to remember are 48 and 32. Heat the chocolate to 48ºC. Remove from heat and stir in more pieces of unmelted chocolate until the chocolate is reduce to 32ºC