trial

TRIAL noun

[ C,U ] uk/traɪəl/ us trial noun [C, U]
(TEST)

a test of something new to find out if it is safe, works correctly, etc

испытание
The drug is currently undergoing clinical trial s.  trial and error
a way of learning the best way to do something by trying different methods

метод проб и ошибок
There aren't any instructions with it - it's just a matter of trial and error.