Am trying to get into shape a garden containing some quite hard (but
seemingly good) top soil, but it has quite a lot of lumps of clay in it
(dug up from the clay bed from about a foot below) some time in the past.

I have some ready access to a endless supply of rotted leaf mold heaped
up from somewhere nearby and similarly a lot of old lawn grass cuttings.

With the intention of growing just flowers and shrubs (no veggies) in
the garden, should i try to remove all the lumps of clay ( a lot of them
are only a couple of cm across) ?

Also what quantities/ratios of mold and or grass cuttings should i mix
in, if you even think this is an advisable thing to do.

Many thanks for any advice.