Regular verbs: just add -ed
Most English verbs are regular. To make the past, just add -ed.
Walk → walked. Talk → talked. Work → worked. Play → played. Cook → cooked.
If the verb ends in -e already, just add -d: live → lived, love → loved.
If it ends in consonant + y, change y to ied: study → studied, try → tried, cry → cried.
If it is one syllable ending in consonant-vowel-consonant, double the last letter: stop → stopped, plan → planned.