How do I start baby-led weaning?

For me I started with mashed avocadoes since it was one of the easiest food to prepare; no steaming is required. What I did was to leave chunks of avocado on his tray and he would pick it up and start experimenting with it. Just to share, maybe only 20% went into his mouth so do expect a lot of mess! It's quite common for babies to play with their foods so don't worry if most of it doesn't go into his mouth but eventually he will learn, especially if he loves a certain type of food (my son loves blueberries!). His main source of nutrients is still from his milk so you don't have to worry if he has eaten enough. Babies will throw their food about once he's done with it :)