How to grow avocados is a question with a few answers possible. First it depends on how soon and if you want the tree to fruit. Grown from the seed an avocado fruit will take about ten years to mature and bear fruit - and this will only happen if.
Reuse an old tree to make a log pathway in your garden. Good use of "yard" trees and other wood that can't be milled; works much better in climates without termites. Good drainage under the log rounds will make the path last longer.
Log Bird Feeder - 23 DIY Birdfeeders That Will Fill Your Garden With Birds (my note: I haven't looked at all of these, but at least one is a terrible idea. The window birdfeeder -- birds could fly into the glass and hurt themselves.