Translation:I will put the watch in the bag.
"a watch" and "the watch" makes Duo detect two different meanings. By default, a watch would be translated as "1 watch". I remember a few sections back "have a bento" translating to the words "have 1 bento".
Probably a bug in the code, could be more correct than "a watch". All I'm saying is report it.
Both are correct. In Japanese it is more important which particle you use than the order (but verbs always at the end). In this case を tells what the object is (the wallet) and に where you put it (in the bag). Now be careful, there is always exception where order is important.
I studied up on Japanese grammar early on to get a feel for it.
English: Subject, Verb, Object. Japanese: Subject, Object, Verb.
It causes confusion at first, but what I did was read an English sentence backwards (minus the subject) to translate the Japanese sentence while being grammatically correct. It's an odd trick, and I want to explain it but I can't find the words to describe it.