Because Magic templating is consistent, if youre looking for a particular effect on a card, you can start with a card you already know to find the general, searchable template
The lack of haste means Mishra needs to live, but Phyrexian Dragon Engine has Unearth, so you can get that on the field from grave with haste, swing in, and get the meld
Then, select the deck you want to personalize, and when editing that deck, go to More Details, to the right: Notice that sometimes you may miss and to the Sideboard (which is right above More Options), but what youre looking for is the screen shown below: Within a deck's details, you can set individual preferences for companions, sleeves and avatars for when you play that deck
Molten Destruction
This one is an interesting card overall, but it wont be played immediately in many decks as it is a bit restrictive