If your struggling id reccomend playing the default 4-4-2 until you get used to how things work. Its a good solid and very simple tactic ideal for beginners and people who don't want to get bogged down in tactics. Its what i use until i get used to the match engine. Just create a 442 on the wizard and select default for everything. The only change i make is i use wingers instead of wide midfielders. Screenshot of how it should look below:
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Also like Sean said its important not to make drastic changes to your tactics all the time. Let your team get used to how you want them to play. Keep an eye on the familiarity gage. This is a good solid and simple base for you to get used to the game, as you become more confident you can start making small tweaks. Good luck.