Trying to create a homebrew item and struggling

Hi all

I'm trying to create a magic item that has a couple of characteristics.

1. The user is a given a once per day teleport akin to Misty Step (but flavoured as Greyfade Leap)

2. The user can also get advantage on Investigation checks for an hour once per day (the hour thing is probably just flavour)

Nothing I do seems to work. I've got the advantage on investigation however it's permanent, and I can't get the spell to show at all.

Any help will be appreciated :-)

For the spell, give it a Min and Max charge of 1 and give the item 1 charge. As for the other thing, temporary effects are not supported by DDB. 

Ah, that's a bit disappointing but I guess I can manage. Thanks for the help :-)