All 5 Uses

however
in
Flora & Ulysses
(Auto-generated)

TERRIBLE THINGS CAN HAPPEN TO YOU/did not, however, detail exactly how someone was supposed to give CPR to a squirrel.
p. 14.7 *

however = a word used to connect contrasting ideas as when using though, in spite of that, in contrast, nevertheless, etc.
However, the squirrel was still a squirrel.
p. 18.8
Words had appeared above his head, however, and Flora's father had read those words to her so many times that she could recite them by heart: HE IS AN UNASSUMING JANITOR.
p. 38.6
I'm not certain, however, if it can cause actual shrinkage.
p. 59.5
I have never claimed to be able to smell everything; however, it is true that right now I am smelling squirrel.†
p. 145.9

Definitions:

(1) (however as in: However, complications may...)
though (or another expression that connects contrasting ideas)

Based on idea 1 we might not expect idea 2, but this is a way of saying that even though idea 1 exists, we still have idea 2. Synonyms include in spite of that, despite that, nevertheless, nonetheless, on the other hand, in contrast and but.
(2) (however as in: However much she tried...)
to whatever degree (regardless of how much; or whatever unspecified amount)
(3) (however as in: However you do it, get it done!)
in whatever way
(4) (meaning too rare to warrant focus)
Much more rarely (and arguably incorrectly), however can be used to intensify the word how, as when one says "However did you find her?" Grammarians would suggest using two words for that usage: "How ever did you find her?"