From the limited available resources online, i was able to determine at first that soft adjectives is just with the stem ending ний as explained on these websites (http://masterrussian.com/aa040801a.shtml)(http://www.russianlessons.net/grammar/adjectives.php) but then when i was doing some exercises that required me to conjugate adjectives to different cases i ran into some adjectives that took the soft stem ending instead of the hard adjective ending which i thought it would be. Example: горячий чай (nominative singular case) --> горячему чаю (dative singular case) I don't understand why this would take the soft adjective declensions rather than hard adjective declensions.
Another thing i could not understand the conjugation of: мягкий ковёр --> мягкому ковёр Why would it not be мягкему instead of the correct answer for the declension in the dative case мягкому.
i have been looking at the definition of soft adjectives and why they are formed on https://en.wikibooks.org/wiki/Russian/Grammar/Adjectives and understand that they are formed because of the 7 letter spelling rule, but it still doesn't explain why some adjectives are declined as if they are soft when they don't end in the stem ний. Is it just best to memorize which of the adjectives are soft because i cannot find any information online about this subject.