They have strings one ties in a knot at the weekend (5)
I believe the answer is:
kites
'they have strings one' is the definition.
The definition suggests an adverb but the answer is not.
'ties in a knot at the weekend' is the wordplay.
'in a knot' indicates an anagram.
'at' means one lot of letters go next to another (I've seen this in other clues).
'the weekend' becomes 'k' (I've seen this in other clues).
'ties' is an anagram of 'ites'.
'ites' put after 'k' is 'KITES'.
Can you help me to learn more?
(Other definitions for kites that I've seen before include "Birds of prey - flying toys" , "Aerial toys; birds" , "More than one toy" , "Large hawks or flying toys" , "aircraft" .)