Teaching grammar online is an increasingly necessary practice, but the process is resource-heavy, requiring online tools such as grammar videos. Studies show that current online grammar modules have mixed effectiveness, and none of the studies have examined the effects of the design of these modules. This study investigated whether an online module, designed according to basic multi-media design principles, is effective in helping learners understand the use of the baconstruction. The study also asked how the students respond to the use of the online module. The findings show that the online module improved learners’ understanding and use of the ba construction. It also found that the students enjoyed using the online module and would like to have similar opportunities to learn grammar via multimedia online modules.