Here is an example where both (1) a particular key must sign the minting transaction and (2) the transaction must occur before a particular slot:
"type" : "all",
"scripts" : [
"type" : "sig",
"keyHash" : "b395c1a9464d419c69d05c148a19d44130c249abfb990c6a3fcd0b07"
"type" : "before",
"slot" : 25251428
You can mint as many tokens of any asset name and quantity that you want before the deadline (either in one transaction or multiple transactions), as long as you sign with that key. No one else can ever mint tokens under this policy (because they don’t have the key) and even you cannot mint any more after the deadline. Is this what you want? If you just mint one of each asset name, then after the deadline they would be considered NFTs; if you mint more than on of an asset name, then it would be considered a fungible native token.
I’m sure the Cardano website has instructions, but I lost track of them after that website was reorganized. Maybe someone can post the latest link?