I am now a gardener

We have lived, up until now, in houses with lawns and simple borders. My main gardening tasks were to keep the lawns mown and to keep the worst of the weeds at bay (weeds are just plants that are really easy to grow, right?)
That changed recently when we moved house with a rather different gardening proposition. This one has mature trees, a terrace, a small orchard, some large veg patches and a cage for growing soft fruit.
Really looking forward to getting stuck in, but massively intimidated by not knowing what to do when, and therefore wasting my effort and making things worse, not better.
I am hoping that the Gardeners World Almanac is going to be my guide, telling what to do and when to do it.
There is a plan to create a wildflower meadow in the orchard and plant some easy veg too - aiming for our own Brussel sprouts for Christmas this year. But first, I am on a mission to clear out those easy to grow plants (weeds) and work out how compost works.
Any tips, or things to avoid appreciated.
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