Largely adapted from the reference document and my experience on jp

Step 0: Pick and train who you like and use the best cards you have (level them up!)
Step 1: Raise all of your support card bonds to orange bar (80+). This will unlock friendship (rainbow) training for a big stat gain boost
Step 2: Follow the flowchart for basic short term (turn by turn) strategy
Step 3: Start thinking about reasons to deviate from the flowchart, such as playing beyond the current turn with managing energy and/or taking suboptimal training categories simply to boost a stat you need.

Go play with this for a bit, see how you feel, and refer to my Intermediate training tips or ideas to get you started for some more ideas

Also give my week 1 FAQs a read Frequently asked day 1 questions and Common training questions FAQ (Valid for first month)

Re: Skills and how they affect you Quant's week 1 skills guide for uma

Word of warning:
Launch version of global has several mechanics that are different to modern JP or as described in the reference document. At best it's misleading, at worst it is actively harmful. Some of these misunderstandings have come through from content creators or elsewhere, just be careful with what you're reading for information and don't dive too deep this early into the game.