Torments with harmful things under the sleeping place (8)
I believe the answer is:
bedevils
'torments' is the definition.
('bedevil' can be a synonym of 'torment')
'harmful things under the sleeping place' is the wordplay.
'harmful things' becomes 'evils' (I can't explain this - if you can you should believe this answer much more).
'under' means one lot of letters go next to another (in a down clue, some letters go below others).
'the sleeping place' becomes 'bed' (I've seen this before).
'evils' after 'bed' is 'BEDEVILS'.
'with' is the link.
Can you help me to learn more?
(Other definitions for bedevils that I've seen before include "is distressing" , "Causes continual difficulties or trouble" , "Torments" .)