Delve Teams/How to Make

How do I make a Delve team??? Do I use my regular troop inventory??? I am just starting Kyrstara exploring and am wondering how I make a Delve Team to explore the dungeons. Is there a guide that I am not finding. Please help.

How do I make a Delve team??? I am waiting to start exploring the Delves.

First things first, what exactly do you mean - delves or dungeon - 'cause they are different things.

You get dungeon by doing Drifting Sands quests and there are no restrictions for teams - use whatever you like.
Delves you get in the underworld. As for the team - any hero weapon you like, troops from the list that are shown to you once you enter the team composition menu (they pre-select all the allowed troops for you).

First, once you beat a Delve difficulty, you can never go back. So, I recommend you keep a faction at level 20 forever. This gives you an option on days you just want to earn some chaos shards without the stress of level 200 opponents. (I suggest Sea of Sorrows for this purpose.)

Now, for actual team compositions, look for three kinds of troops/weapons:
(1) those that do scaling damage. That is, as enemy stats get higher, so does the spell effect. Think Tesla, or Mang (hero weapon), or Faunessa.
(2) legendary or mythic troops that have useful spells or third traits. The barrier provided by Jotnar Stormshield is handy when enemy attacks get into the 200s. Or Queen Mab’s freeze can protect you against lucky sky drops for the AI. (Personally, I love love love The Possessed King’s third trait. I never even cast his spell, but that trait is so dang useful!)
(3) troops that safely generate mana. This will usually be converters like Valkyrie or Alchemist—make sure you only use it when you can get an extra turn! Exploders like Gorgotha can work, but you risk letting the board fall into a lucky pattern for the AI. Legendary troops that convert two colors at once are also options.