Thanks for joining!

1. There are a lot of ways you can do it. Most basic is this: you do the set up entirely on your own.

You set up a wallet with 1 primary key (this is your key which you use to spend from the wallet) and 1 inheritance/recovery key. For this key, coins are timelocked for some a customizeable length of time (up to ~15 months). As long as you use your primary key to spend the coins (even just as a self-send to refresh the timelock) before the timelock expires, the inheritance key will not become active.

This means you could give it to your heir or to an executor without worrying that they will sweep the funds.

2. In the case where you want to create an expanding multisig, where you have a 2 of 2 with a third recovery key that becomes active later if you lose a key:

You actually create a 2 of 3 wallet (only three keys total), but coins are timelocked for the recovery key and it cannot be used unless the primary keys don't spend for a time longer than the timelock.

This is pretty useful if you want to do a multisig but don't have a secure place to keep the extra keys in the threshold: you can do something like a 2 of 2 which would normally be risky (what if you lose one of the keys?) knowing that you have a backup key (or multiple) that you can use in a worst-case scenario.