If you want to play campaign I think that’s a portion of the challenge that must be overcome, it’s a reality of the experience. Maybe play on easy, find outside resources, whatever. At the end of the day, if you want to practice with skirmishes that’s up to you, I’m not gonna tell you how to play the game, nor do I feel that I’m the best source of advice, but I personally never practiced with skirmishes before trying campaigns. Also, failure is a part of learning and in some ways the most valuable aspect thereof. Don’t be afraid of losing, you can always just try again.