The accent mark above a letter doesn't mean the vowel is stressed. It means it's long.
a
like 'a' in "barn"
e
like 'e' in "red"
ě
like 'ye' in "yet"
i
like 'i' in "machine"
o
like 'o' in "mole"
u
like 'ou' in "you"
ů
same as 'u', but corresponds to 'o' in other languages
y
same as 'i'
