Hello,
i would say the best way is to just start without worrying too much, and if it all goes wrong you can start again.
Maybe pick a really good team like Barcalona and you can get through a season learning how to balance your team, play around with some tactics, and get used to planning a whole season without worrying about having to scout out a load of new players.
Keep half an eye on the calendar, and remember to rest players (dont even put them on the subs bench) before big games like the champions league.
Play the first 10 games just trying to get to know your team, start playing around with tactics, and see how you get on.
Then once you know what you're doing, you can start again with a team that gives you a bit more of a realistic challenge...