Large Raised Bed

Hi Everyone.  I am very new to both gardening and the forum, so apologies in advance if I am asking silly questions etc.

I have inherited a large raised bed in the corner of my garden.  It is in the shape of an arc (bit like a quarter of a circle), and has a brick low wall surrounding it, with fences on the two straight sides.  It is quite large, and has a bit of a slope - downwards towards the low wall.  The trouble is, there are about 4 large tree stumps and associated roots on the straight edges, and it is overgrown with roots and weeds, as well as having been used as a dumping ground for building rubble & rocks in the past.

I am not entirely sure what to do with it, I am thinking of getting some kind of little patio in the corner to put a seat on, and then planting the rest with a rockery (maybe).

Does this sound utterly ridiculous?  I have never attempted any hard landscaping before, and am both nervous and apprehensive about the tree stumps and the sloping ground.

If you have any thoughts/advice, I'd be really grateful.  Thank you!