First time doing treasure maps question.

I tried my first maps yesterday with my sister and got one portal out of them. We got destroyed after ignoring the recommended 8-player recommendation. My FC is not that active, so I’m going to set up a Party Finder tonight for 2 maps that picked I up from the Market Board. My question is what is the general consensus on this? Such as how many healers/tanks should I have? Loot rules and my final question is can I start a party finder AFTER I locate the portal or do I have to start the finder before I find the first treasure? Thanks everyone! Still learning this! I’m hoping people don’t get salty for not pulling a portal lol