On every home profile, you'll find a blue heart in the top-right corner. Click that to make a favourite, or click again to unfavourite the home. Favourites are organised into wishlists. A wishlist can be for anything you like: a holiday, a country, a type of exchange ... whatever works for you. Tick the wishlist to which you want to add your favourite, or create a new one. Once you've done that, you'll see that home appear with a blue pin on the map and you can search for your favourites using the main navigation bar, Homes/Favourites, or using the favourites filter.